Quarterly report pursuant to Section 13 or 15(d)

DERIVATIVE FINANCIAL INSTRUMENTS - Narrative (Details)

v3.20.1
DERIVATIVE FINANCIAL INSTRUMENTS - Narrative (Details)
$ in Millions
 3 Months Ended 12 Months Ended
Mar. 31, 2020
USD ($)
group
Dec. 31, 2019
USD ($)
Dec. 31, 2019
USD ($)
Derivative [Line Items]      
Increase (decrease) to net interest income due to derivative adjustment $ 16 $ (14)  
Fair value hedging adjustments (84)   $ (93)
Derivative, Notional Amount 27,415 25,927 25,927
Credit risks from interest rate swaps used for trading purposes 997 407 407
Derivative Liability $ 306 104 104
Number of primary groups | group 2    
Aggregate credit risk, net of collateral $ 85 22 22
Investment securities and cash collateral pledged by Huntington 189    
Investment securities and cash collateral pledged to Huntington 499    
Derivative used in trading activity      
Derivative [Line Items]      
Net derivative asset (liability) 64 87 87
Derivative financial instruments used by Huntington on behalf of customers including offsetting derivatives, notional value 32,000 30,000 30,000
Derivative used in Mortgage Banking Activities      
Derivative [Line Items]      
Derivative, Notional Amount 490 778 778
Derivative, Fair Value, Net (6) 6 6
Fair Value Hedging      
Derivative [Line Items]      
Derivative, Notional Amount 8,040 7,540 7,540
Cash Flow Hedging      
Derivative [Line Items]      
Derivative, Notional Amount 19,375 18,387 18,387
Commitments to Sell Loans [Member]      
Derivative [Line Items]      
Commitments to sell residential real estate loans 2,200 1,400 1,400
Loans Payable [Member]      
Derivative [Line Items]      
Derivative, Notional Amount 19,375 18,375 18,375
Loans Payable [Member] | Fair Value Hedging      
Derivative [Line Items]      
Derivative, Notional Amount 0 0 0
Loans Payable [Member] | Cash Flow Hedging      
Derivative [Line Items]      
Derivative, Notional Amount $ 19,375 $ 18,375 $ 18,375