Quarterly report pursuant to Section 13 or 15(d)

DERIVATIVE FINANCIAL INSTRUMENTS - Narrative (Details)

v3.7.0.1
DERIVATIVE FINANCIAL INSTRUMENTS - Narrative (Details)
 3 Months Ended 6 Months Ended
Jun. 30, 2017
USD ($)
Jun. 30, 2016
USD ($)
Jun. 30, 2017
USD ($)
group
Jun. 30, 2016
USD ($)
Dec. 31, 2016
USD ($)
Derivative [Line Items]          
Increase (decrease) to net interest income due to derivative adjustment $ 6,000,000 $ 19,000,000 $ 16,000,000 $ 40,000,000  
Gain (loss) to be reclassified during next 12 months, net (2,000,000)   (2,000,000)    
Purchase of interest rate caps and derivative financial instruments, notional value 9,600,000,000   9,600,000,000    
Total notional amount corresponds to trading assets, fair value 1,000,000   1,000,000    
Notional amount corresponds to trading liabilities, fair value (less than) 2,000,000   2,000,000    
Credit risks from interest rate swaps used for trading purposes 156,000,000   $ 156,000,000   $ 196,000,000
Number of primary groups | group     2    
Aggregate credit risk, net of collateral 44,000,000   $ 44,000,000   26,000,000
Investment securities and cash collateral pledged by Huntington 120,000,000   120,000,000    
Investment securities and cash collateral pledged to Huntington 53,000,000   53,000,000    
Swap          
Derivative [Line Items]          
Derivative Liability 6,000,000   6,000,000    
Derivative used in trading activity          
Derivative [Line Items]          
Net derivative asset (liability) 80,000,000   80,000,000   80,000,000
Derivative financial instruments used by Huntington on behalf of customers including offsetting derivatives, notional value 21,000,000,000   21,000,000,000   21,000,000,000
Derivative used in Mortgage Banking Activities          
Derivative [Line Items]          
Purchase of interest rate caps and derivative financial instruments, notional value 228,000,000   228,000,000   300,000,000
Gains (losses) related to derivative instruments Included in total MSR 2,000,000 $ 6,000,000 1,000,000 $ 18,000,000  
Share Swap Economic Hedge          
Derivative [Line Items]          
Purchase of interest rate caps and derivative financial instruments, notional value 28,000,000   28,000,000   $ 20,000,000
Derivative, Fair Value, Net 11,000,000   11,000,000    
Deposits          
Derivative [Line Items]          
Purchase of interest rate caps and derivative financial instruments, notional value 0   0    
Fair Value Hedging          
Derivative [Line Items]          
Purchase of interest rate caps and derivative financial instruments, notional value 7,675,000,000   7,675,000,000    
Fair Value Hedging | Deposits          
Derivative [Line Items]          
Purchase of interest rate caps and derivative financial instruments, notional value 0   0    
Cash Flow Hedging          
Derivative [Line Items]          
Purchase of interest rate caps and derivative financial instruments, notional value 1,925,000,000   1,925,000,000    
Cash Flow Hedging | Deposits          
Derivative [Line Items]          
Purchase of interest rate caps and derivative financial instruments, notional value $ 0   $ 0