Huntington Bancshares Incorporated Annual report pursuant to Section 13 and 15(d)

FAIR VALUES OF ASSETS AND LIABILITIES - Significant Unobservable Level 3 Inputs (Details)

FAIR VALUES OF ASSETS AND LIABILITIES - Significant Unobservable Level 3 Inputs (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Derivative assets gross	$ 322	$ 420
Gross amounts of recognized liabilities	331	371
Available-for-sale and other securities	15,469	15,563
Consumer loans	$ 93	82
Derivative Liabilities \| Maximum \| Consensus Pricing \| Level 3
Quantitative information about level 3 fair value measurements
Fair Value Inputs, Timing of the resolution of the litigation	Jun. 30, 2020
Derivative Liabilities \| Minimum \| Consensus Pricing \| Level 3
Quantitative information about level 3 fair value measurements
Fair Value Inputs, Estimated conversion factor	165.00%
Fair Value Inputs, Estimated growth rate of Visa Class A shares	7.00%
Discount rate	3.00%
Fair Value Inputs, Timing of the resolution of the litigation	Dec. 31, 2017
Derivative Liabilities \| Weighted Average \| Consensus Pricing \| Level 3
Quantitative information about level 3 fair value measurements
Fair Value Inputs, Timing of the resolution of the litigation	Jun. 30, 2020
MSRs \| Maximum \| Discounted cash flow \| Level 3
Quantitative information about level 3 fair value measurements
Constant prepayment rate	33.00%
Spread over forward interest rate swap rates	0.100
MSRs \| Minimum \| Discounted cash flow \| Level 3
Quantitative information about level 3 fair value measurements
Constant prepayment rate	8.00%
Spread over forward interest rate swap rates	0.080
MSRs \| Weighted Average \| Discounted cash flow \| Level 3
Quantitative information about level 3 fair value measurements
Constant prepayment rate	12.00%
Spread over forward interest rate swap rates	0.080
Derivative Assets \| Maximum \| Consensus Pricing \| Level 3
Quantitative information about level 3 fair value measurements
Net market price	20.00%
Estimated Pull through %	100.00%
Derivative Assets \| Minimum \| Consensus Pricing \| Level 3
Quantitative information about level 3 fair value measurements
Net market price	(5.00%)
Estimated Pull through %	3.00%
Derivative Assets \| Weighted Average \| Consensus Pricing \| Level 3
Quantitative information about level 3 fair value measurements
Net market price	2.00%
Estimated Pull through %	75.00%
Municipal securities \| Maximum \| Discounted cash flow \| Level 3
Quantitative information about level 3 fair value measurements
Discount rate	10.00%
Cumulative default	64.00%
Loss given default	90.00%
Municipal securities \| Minimum \| Discounted cash flow \| Level 3
Quantitative information about level 3 fair value measurements
Discount rate	0.00%
Cumulative default	0.00%
Loss given default	5.00%
Municipal securities \| Weighted Average \| Discounted cash flow \| Level 3
Quantitative information about level 3 fair value measurements
Discount rate	4.00%
Cumulative default	3.00%
Loss given default	24.00%
Asset-backed securities \| Maximum \| Discounted cash flow \| Level 3
Quantitative information about level 3 fair value measurements
Constant prepayment rate	72.00%
Discount rate	7.00%
Cumulative default	53.00%
Loss given default	100.00%
Cure given deferral	50.00%
Asset-backed securities \| Minimum \| Discounted cash flow \| Level 3
Quantitative information about level 3 fair value measurements
Constant prepayment rate	0.00%
Discount rate	7.00%
Cumulative default	3.00%
Loss given default	90.00%
Cure given deferral	50.00%
Asset-backed securities \| Weighted Average \| Discounted cash flow \| Level 3
Quantitative information about level 3 fair value measurements
Constant prepayment rate	7.00%
Discount rate	7.00%
Cumulative default	7.00%
Loss given default	100.00%
Cure given deferral	50.00%
Automobile \| Maximum \| Discounted cash flow \| Level 3
Quantitative information about level 3 fair value measurements
Constant prepayment rate	18.00%
Discount rate	22.00%
Life of pool cumulative losses	2.10%
Automobile \| Minimum \| Discounted cash flow \| Level 3
Quantitative information about level 3 fair value measurements
Constant prepayment rate	700.00%
Discount rate	0.20%
Life of pool cumulative losses	2.10%
Automobile \| Weighted Average \| Discounted cash flow \| Level 3
Quantitative information about level 3 fair value measurements
Constant prepayment rate	8.00%
Discount rate	9.00%
Life of pool cumulative losses	2.10%
Recurring
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
MSRs	$ 11	14
Available-for-sale and other securities	14,888	15,015
Recurring \| Level 3
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
MSRs	11	14
Derivative assets gross	6	6
Gross amounts of recognized liabilities	5	8
Available-for-sale and other securities	3,191	2,874
Consumer loans	38	48
Fair Value
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
Available-for-sale and other securities	15,469	$ 15,563
Fair Value \| Nonrecurring
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
MSRs	190
Impaired loans	36
Other real estate owned	33
Fair Value \| Nonrecurring \| Level 3
Fair Value Inputs, Assets and Liabilities, Quantitative Information [Line Items]
MSRs	190
Impaired loans	36
Other real estate owned	$ 33