Quarterly report pursuant to Section 13 or 15(d)

DERIVATIVE FINANCIAL INSTRUMENTS - Narrative (Details)

v3.19.1
DERIVATIVE FINANCIAL INSTRUMENTS - Narrative (Details)
$ in Millions
 3 Months Ended 12 Months Ended
Mar. 31, 2019
USD ($)
group
Dec. 31, 2018
USD ($)
Dec. 31, 2018
USD ($)
Derivative [Line Items]      
Purchase of interest rate caps and derivative financial instruments, notional value $ 9,552 $ 4,877 $ 4,877
Increase (decrease) to net interest income due to derivative adjustment (14) 1  
Fair value hedging adjustments (119)   (127)
Credit risks from interest rate swaps used for trading purposes 237 132 132
Derivative Liability $ 87 187 187
Number of primary groups | group 2    
Aggregate credit risk, net of collateral $ 21 37 37
Investment securities and cash collateral pledged by Huntington 80    
Investment securities and cash collateral pledged to Huntington 76    
Swap      
Derivative [Line Items]      
Derivative Liability 3    
Derivative used in trading activity      
Derivative [Line Items]      
Net derivative asset (liability) 82 92 92
Derivative financial instruments used by Huntington on behalf of customers including offsetting derivatives, notional value 28,000 26,000 26,000
Derivative used in Mortgage Banking Activities      
Derivative [Line Items]      
Purchase of interest rate caps and derivative financial instruments, notional value 650 0 0
Derivative, Fair Value, Net   (4) (4)
Fair Value Hedging      
Derivative [Line Items]      
Purchase of interest rate caps and derivative financial instruments, notional value 5,790 4,865 4,865
Cash Flow Hedging      
Derivative [Line Items]      
Purchase of interest rate caps and derivative financial instruments, notional value 2,762 12 12
Commitments to Sell Loans [Member]      
Derivative [Line Items]      
Commitments to sell residential real estate loans $ 900 $ 800 $ 800