Annual report pursuant to Section 13 and 15(d)

Held-to-Maturity Securities (Details)

v2.4.1.9
Held-to-Maturity Securities (Details) (USD $)
In Thousands, unless otherwise specified
Dec. 31, 2014
Dec. 31, 2013
Contractual maturities of held-to-maturity securities    
Held-to-maturity securities, Total $ 3,379,905us-gaap_HeldToMaturitySecurities $ 3,836,667us-gaap_HeldToMaturitySecurities
Held-to-maturity Securities, Fair Value 3,382,715us-gaap_HeldToMaturitySecuritiesFairValue 3,760,898us-gaap_HeldToMaturitySecuritiesFairValue
Amortized cost, gross unrealized gains and losses, and fair value by investment category    
Held-to-maturity securities, Total 3,379,905us-gaap_HeldToMaturitySecurities 3,836,667us-gaap_HeldToMaturitySecurities
Held-to-maturity Securities, Gross Gain (26,083)us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain (6,349)us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain
Held-to-maturity Securities, Gross Losses (23,273)us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss (82,118)us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss
Held-to-maturity securities, fair value 3,382,715us-gaap_HeldToMaturitySecuritiesFairValue 3,760,898us-gaap_HeldToMaturitySecuritiesFairValue
Continuous Unrealized Loss Position    
Total Temporarily Impaired Securities, Less Than Twelve Months, Fair Value 752,484us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue 3,001,774us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
Total Temporarily Impaired Securities Unrealized Losses, Less Than Twelve Months, Fair Value (6,135)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss (79,766)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
Total Temporarily Impaired Securities, Over Twelve Months, Fair Value 693,757us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue 22,548us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
Total Temporarily Impaired Securites, Unrealized Losses Over Twelve Months (17,138)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss (2,352)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
Total Temporarily Impaired Securities, Fair Value 1,446,241us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue 3,024,322us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue
Total Temporarily Impaired Securities, Unrealized Losses (23,273)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss (82,118)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss
Federal agencies - mortgage backed securities [Member]    
Contractual maturities of held-to-maturity securities    
Held-to-maturity Securities, Under 1 year 0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Held-to-maturity Securities, 1-5 years 0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Held-to-maturity Securities, 6-10 years 24,901us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
24,901us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Held-to-maturity Securities, Over 10 years 3,136,460us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
3,574,156us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Held-to-maturity securities, Total 3,161,361us-gaap_HeldToMaturitySecurities
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
3,599,057us-gaap_HeldToMaturitySecurities
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Fair Value, Under 1 year 0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Fair Value, 1-5 years 0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Fair Value, 6-10 years 24,263us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
22,549us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Fair Value, Over 10 years 3,140,194us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
3,506,018us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Held-to-maturity Securities, Fair Value 3,164,457us-gaap_HeldToMaturitySecuritiesFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
3,528,567us-gaap_HeldToMaturitySecuritiesFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Amortized cost, gross unrealized gains and losses, and fair value by investment category    
Held-to-maturity securities, Total 3,161,361us-gaap_HeldToMaturitySecurities
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
3,599,057us-gaap_HeldToMaturitySecurities
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Held-to-maturity Securities, Gross Gain (24,832)us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
(5,573)us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Held-to-maturity Securities, Gross Losses (21,736)us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
(76,063)us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Held-to-maturity securities, fair value 3,164,457us-gaap_HeldToMaturitySecuritiesFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
3,528,567us-gaap_HeldToMaturitySecuritiesFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Continuous Unrealized Loss Position    
Total Temporarily Impaired Securities, Less Than Twelve Months, Fair Value 707,934us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
2,849,198us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Total Temporarily Impaired Securities Unrealized Losses, Less Than Twelve Months, Fair Value (5,550)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
(73,711)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Total Temporarily Impaired Securities, Over Twelve Months, Fair Value 622,026us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
22,548us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Total Temporarily Impaired Securites, Unrealized Losses Over Twelve Months (16,186)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
(2,352)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Total Temporarily Impaired Securities, Fair Value 1,329,960us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
2,871,746us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Total Temporarily Impaired Securities, Unrealized Losses (21,736)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
(76,063)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_MortgageBackedSecuritiesIssuedByUSGovernmentSponsoredEnterprisesMember
Other Federal Agencies [Member]    
Contractual maturities of held-to-maturity securities    
Held-to-maturity Securities, Under 1 year 0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
Held-to-maturity Securities, 1-5 years 0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
Held-to-maturity Securities, 6-10 years 54,010us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
38,588us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
Held-to-maturity Securities, Over 10 years 156,553us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
189,999us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
Held-to-maturity securities, Total 210,563us-gaap_HeldToMaturitySecurities
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
228,587us-gaap_HeldToMaturitySecurities
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
Fair Value, Under 1 year 0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
Fair Value, 1-5 years 0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
Fair Value, 6-10 years 54,843us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
39,075us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
Fair Value, Over 10 years 155,821us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
185,097us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
Held-to-maturity Securities, Fair Value 210,664us-gaap_HeldToMaturitySecuritiesFairValue
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
224,172us-gaap_HeldToMaturitySecuritiesFairValue
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
Amortized cost, gross unrealized gains and losses, and fair value by investment category    
Held-to-maturity securities, Total 210,563us-gaap_HeldToMaturitySecurities
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
228,587us-gaap_HeldToMaturitySecurities
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
Held-to-maturity Securities, Gross Gain (1,251)us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
(776)us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
Held-to-maturity Securities, Gross Losses (1,150)us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
(5,191)us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
Held-to-maturity securities, fair value 210,664us-gaap_HeldToMaturitySecuritiesFairValue
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
224,172us-gaap_HeldToMaturitySecuritiesFairValue
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
Continuous Unrealized Loss Position    
Total Temporarily Impaired Securities, Less Than Twelve Months, Fair Value 36,956us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
144,417us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
Total Temporarily Impaired Securities Unrealized Losses, Less Than Twelve Months, Fair Value (198)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
(5,191)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
Total Temporarily Impaired Securities, Over Twelve Months, Fair Value 71,731us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
0us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
Total Temporarily Impaired Securites, Unrealized Losses Over Twelve Months (952)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
0us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
Total Temporarily Impaired Securities, Fair Value 108,687us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
144,417us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
Total Temporarily Impaired Securities, Unrealized Losses (1,150)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
(5,191)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= hban_OtherFederalAgenciesMember
Municipal securities [Member]    
Contractual maturities of held-to-maturity securities    
Held-to-maturity Securities, Under 1 year 0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
Held-to-maturity Securities, 1-5 years 0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
Held-to-maturity Securities, 6-10 years 0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
Held-to-maturity Securities, Over 10 years 7,981us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
9,023us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsNetCarryingAmount
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
Held-to-maturity securities, Total 7,981us-gaap_HeldToMaturitySecurities
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
9,023us-gaap_HeldToMaturitySecurities
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
Fair Value, Under 1 year 0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesWithinOneYearFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
Fair Value, 1-5 years 0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterOneThroughFiveYearsFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
Fair Value, 6-10 years 0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
0us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterFiveThroughTenYearsFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
Fair Value, Over 10 years 7,594us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
8,159us-gaap_HeldToMaturitySecuritiesDebtMaturitiesAfterTenYearsFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
Held-to-maturity Securities, Fair Value 7,594us-gaap_HeldToMaturitySecuritiesFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
8,159us-gaap_HeldToMaturitySecuritiesFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
Amortized cost, gross unrealized gains and losses, and fair value by investment category    
Held-to-maturity securities, Total 7,981us-gaap_HeldToMaturitySecurities
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
9,023us-gaap_HeldToMaturitySecurities
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
Held-to-maturity Securities, Gross Gain 0us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
0us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
Held-to-maturity Securities, Gross Losses (387)us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
(864)us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
Held-to-maturity securities, fair value 7,594us-gaap_HeldToMaturitySecuritiesFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
8,159us-gaap_HeldToMaturitySecuritiesFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
Continuous Unrealized Loss Position    
Total Temporarily Impaired Securities, Less Than Twelve Months, Fair Value 7,594us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
8,159us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
Total Temporarily Impaired Securities Unrealized Losses, Less Than Twelve Months, Fair Value (387)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
(864)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
Total Temporarily Impaired Securities, Over Twelve Months, Fair Value 0us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
0us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
Total Temporarily Impaired Securites, Unrealized Losses Over Twelve Months 0us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
0us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
Total Temporarily Impaired Securities, Fair Value 7,594us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
8,159us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
Total Temporarily Impaired Securities, Unrealized Losses (387)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
(864)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_MunicipalBondsMember
Total U.S. Government backed agencies [Member]    
Contractual maturities of held-to-maturity securities    
Held-to-maturity securities, Total 3,371,924us-gaap_HeldToMaturitySecurities
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
3,827,644us-gaap_HeldToMaturitySecurities
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
Held-to-maturity Securities, Fair Value 3,375,121us-gaap_HeldToMaturitySecuritiesFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
3,752,739us-gaap_HeldToMaturitySecuritiesFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
Amortized cost, gross unrealized gains and losses, and fair value by investment category    
Held-to-maturity securities, Total 3,371,924us-gaap_HeldToMaturitySecurities
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
3,827,644us-gaap_HeldToMaturitySecurities
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
Held-to-maturity Securities, Gross Gain (26,083)us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
(6,349)us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingGain
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
Held-to-maturity Securities, Gross Losses (22,886)us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
(81,254)us-gaap_HeldToMaturitySecuritiesAccumulatedUnrecognizedHoldingLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
Held-to-maturity securities, fair value 3,375,121us-gaap_HeldToMaturitySecuritiesFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
3,752,739us-gaap_HeldToMaturitySecuritiesFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
Continuous Unrealized Loss Position    
Total Temporarily Impaired Securities, Less Than Twelve Months, Fair Value 744,890us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
2,993,615us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThanTwelveMonthsFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
Total Temporarily Impaired Securities Unrealized Losses, Less Than Twelve Months, Fair Value (5,748)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
(78,902)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionLessThan12MonthsAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
Total Temporarily Impaired Securities, Over Twelve Months, Fair Value 693,757us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
22,548us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionTwelveMonthsOrLongerFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
Total Temporarily Impaired Securites, Unrealized Losses Over Twelve Months (17,138)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
(2,352)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPosition12MonthsOrLongerAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
Total Temporarily Impaired Securities, Fair Value 1,438,647us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
3,016,163us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionFairValue
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
Total Temporarily Impaired Securities, Unrealized Losses $ (22,886)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember
$ (81,254)us-gaap_HeldToMaturitySecuritiesContinuousUnrealizedLossPositionAccumulatedLoss
/ us-gaap_DebtSecurityAxis
= us-gaap_USGovernmentSponsoredEnterprisesDebtSecuritiesMember