Quarterly report pursuant to Section 13 or 15(d)

LONG-TERM DEBT (Details)

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LONG-TERM DEBT (Details) - Senior Notes - USD ($)
9 Months Ended
Sep. 30, 2018
Aug. 16, 2018
May 08, 2018
Huntington National Bank Senior Note Due May 2025, 4.00 Percent      
Debt Instrument [Line Items]      
Debt face amount     $ 500,000,000
Debt percent of value     99.686%
Debt stated interest rate     4.00%
Debt Instrument, Redemption Price, Percentage 100.00%    
Debt Issuance Costs, Gross $ 1,000,000    
Huntington National Bank Senior Note Due May 2021, 3.25 Percent      
Debt Instrument [Line Items]      
Debt face amount     $ 750,000,000
Debt percent of value     99.774%
Debt stated interest rate     3.25%
Debt Instrument, Redemption Price, Percentage 100.00%    
Debt Issuance Costs, Gross $ 2,000,000    
Huntington National Bank Senior Note Due October 2023, 3.55 Percent [Domain]      
Debt Instrument [Line Items]      
Debt face amount   $ 750,000,000  
Debt percent of value   99.78%  
Debt stated interest rate   3.55%  
Debt Instrument, Redemption Price, Percentage 100.00%    
Debt Issuance Costs, Gross $ 4,000,000