Annual report pursuant to Section 13 and 15(d)

Derivative Financial Instruments (Details Textuals)

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Derivative Financial Instruments (Details Textuals) (USD $)
 12 Months Ended
Dec. 31, 2012
Dec. 31, 2011
Dec. 31, 2010
Derivative Financial Instruments (Textuals) [Abstract]      
Purchase of interest rate caps and derivative financial instruments, notional value $ 10,512,875,000    
Additional Derivative Financial Instruments (Textuals) [Abstract]      
Aggregate credit risk, net of collateral 17,400,000 36,400,000  
Investment securities and cash collateral pledged by Huntington 181,100,000    
Investment securities and cash collateral pledged to Huntington 162,500,000    
Increase (decrease) to net interest income due to derivative adjustment 107,500,000 113,900,000 192,200,000
Expected after-tax unrealized gains on cash flow hedging derivatives reclassified to earnings 39,600,000,000    
Interest Rate Cap [Member]
      
Derivative Financial Instruments (Textuals) [Abstract]      
Purchase of interest rate caps and derivative financial instruments, notional value 600,000,000    
Interest rate caps sold, value 600,000,000    
Swap [Member]
      
Derivative Financial Instruments (Textuals) [Abstract]      
Total derivative liabilities 400,000,000    
Derivative used in trading activity [Member]
      
Derivative Financial Instruments (Textuals) [Abstract]      
Net derivative liability 63,400,000 53,200,000  
Derivative financial instruments used by Huntington on behalf of customers including offsetting derivatives, notional value 12,000,000,000 10,600,000,000  
Credit risks from interest rate swaps used for trading purposes 296,100,000 309,500,000  
Derivative used in Mortgage Banking Activities [Member]
      
Derivative Financial Instruments (Textuals) [Abstract]      
Net derivative liability 11,752,000 (1,265,000)  
Purchase of interest rate caps and derivative financial instruments, notional value 2,300,000,000 1,700,000,000  
Total notional amount corresponds to trading assets, fair value 6,400,000    
Total notional amount corresponds to trading liabilities, fair value 1,000,000    
MSR hedging gains (losses) 31,300,000 42,100,000 55,000,000
Gains (losses) related to derivative instruments Included in total MSR 31,200,000 42,200,000 64,600,000
Total derivative liabilities $ 2,191,000 $ 8,036,000