Huntington Bancshares Incorporated Quarterly report pursuant to Section 13 or 15(d)

Fair Values of Assets and Liabilities (Significant unobservable Level 3 inputs) (Details 6)

Fair Values of Assets and Liabilities (Significant unobservable Level 3 inputs) (Details 6)	3 Months Ended	12 Months Ended
	Jun. 30, 2015 USD ($)	Dec. 31, 2014 USD ($)
Assets measured at fair value on a recurring basis
Available-for-sale and other securities	$ 10,254,871,000	$ 9,384,670,000
MSRs [Member] \| Maximum [Member] \| Cost Approach Valuation Technique [Member] \| Level 3 [Member]
Quantitative information about level 3 fair value measurements
Constant prepayment rate (CPR)	24.00%	26.00%
Spread over forward interest rate swap rates	1,166	900
Net costs to service	$ 120	$ 79
MSRs [Member] \| Minimum [Member] \| Cost Approach Valuation Technique [Member] \| Level 3 [Member]
Quantitative information about level 3 fair value measurements
Constant prepayment rate (CPR)	5.00%	7.00%
Spread over forward interest rate swap rates	325	228
Net costs to service	$ 26	$ 21
MSRs [Member] \| Weighted Average [Member] \| Cost Approach Valuation Technique [Member] \| Level 3 [Member]
Quantitative information about level 3 fair value measurements
Constant prepayment rate (CPR)	14.00%	16.00%
Spread over forward interest rate swap rates	597	546
Net costs to service	$ 47	$ 40
Derivative Instruments [Member] \| Maximum [Member] \| Market Approach Valuation Technique [Member] \| Level 3 [Member]
Quantitative information about level 3 fair value measurements
Net market price	18.50%	17.50%
Estimated pull thru %	94.00%	91.00%
Derivative Instruments [Member] \| Minimum [Member] \| Market Approach Valuation Technique [Member] \| Level 3 [Member]
Quantitative information about level 3 fair value measurements
Net market price	(4.80%)	(5.10%)
Estimated pull thru %	50.00%	38.00%
Derivative Instruments [Member] \| Weighted Average [Member] \| Market Approach Valuation Technique [Member] \| Level 3 [Member]
Quantitative information about level 3 fair value measurements
Net market price	1.40%	1.70%
Estimated pull thru %	78.00%	75.00%
Municipal securities [Member] \| Maximum [Member] \| Cost Approach Valuation Technique [Member] \| Level 3 [Member]
Quantitative information about level 3 fair value measurements
Discount rate	3.80%	4.90%
Municipal securities [Member] \| Minimum [Member] \| Cost Approach Valuation Technique [Member] \| Level 3 [Member]
Quantitative information about level 3 fair value measurements
Discount rate	0.50%	50.00%
Municipal securities [Member] \| Weighted Average [Member] \| Cost Approach Valuation Technique [Member] \| Level 3 [Member]
Quantitative information about level 3 fair value measurements
Discount rate	2.60%	2.50%
Private label CMO [Member] \| Maximum [Member] \| Cost Approach Valuation Technique [Member] \| Level 3 [Member]
Quantitative information about level 3 fair value measurements
Constant prepayment rate (CPR)	32.60%	32.60%
Probability of default	4.00%	4.00%
Loss severity	64.00%	64.00%
Discount rate	4.00%	7.20%
Private label CMO [Member] \| Minimum [Member] \| Cost Approach Valuation Technique [Member] \| Level 3 [Member]
Quantitative information about level 3 fair value measurements
Constant prepayment rate (CPR)	12.00%	13.60%
Probability of default	0.10%	0.10%
Loss severity	0.00%	0.00%
Discount rate	2.70%	2.70%
Private label CMO [Member] \| Weighted Average [Member] \| Cost Approach Valuation Technique [Member] \| Level 3 [Member]
Quantitative information about level 3 fair value measurements
Constant prepayment rate (CPR)	20.00%	20.70%
Probability of default	0.70%	0.70%
Loss severity	34.80%	33.90%
Discount rate	6.00%	6.00%
Asset-backed Securities [Member] \| Maximum [Member] \| Cost Approach Valuation Technique [Member] \| Level 3 [Member]
Quantitative information about level 3 fair value measurements
Discount rate	11.30%	13.30%
Cumulative prepayment rate	100.00%	100.00%
Cumulative default	100.00%	100.00%
Loss given default	100.00%	100.00%
Cure given deferral	75.00%	75.00%
Asset-backed Securities [Member] \| Minimum [Member] \| Cost Approach Valuation Technique [Member] \| Level 3 [Member]
Quantitative information about level 3 fair value measurements
Discount rate	4.30%	4.30%
Cumulative prepayment rate	0.00%	0.00%
Cumulative default	1.80%	1.90%
Loss given default	85.00%	20.00%
Cure given deferral	0.00%	0.00%
Asset-backed Securities [Member] \| Weighted Average [Member] \| Cost Approach Valuation Technique [Member] \| Level 3 [Member]
Quantitative information about level 3 fair value measurements
Discount rate	5.80%	7.30%
Cumulative prepayment rate	8.90%	10.10%
Cumulative default	14.40%	15.90%
Loss given default	96.00%	94.40%
Cure given deferral	41.70%	32.60%
Automobile Loan [Member] \| Maximum [Member] \| Cost Approach Valuation Technique [Member] \| Level 3 [Member]
Quantitative information about level 3 fair value measurements
Constant prepayment rate (CPR)	154.20%	79.20%
Discount rate	5.00%	5.00%
Life of pool cumulative losses	2.10%	210.00%
Automobile Loan [Member] \| Minimum [Member] \| Cost Approach Valuation Technique [Member] \| Level 3 [Member]
Quantitative information about level 3 fair value measurements
Constant prepayment rate (CPR)	154.20%	79.20%
Discount rate	0.20%	0.30%
Life of pool cumulative losses	2.10%	210.00%
Automobile Loan [Member] \| Weighted Average [Member] \| Cost Approach Valuation Technique [Member] \| Level 3 [Member]
Quantitative information about level 3 fair value measurements
Constant prepayment rate (CPR)	154.20%	79.20%
Discount rate	2.30%	1.50%
Life of pool cumulative losses	2.10%	210.00%