Annual report pursuant to Section 13 and 15(d)

LONG-TERM DEBT - Schedule of Long-Term Debt (Details)

v3.6.0.2
LONG-TERM DEBT - Schedule of Long-Term Debt (Details) - USD ($)
$ in Thousands
 12 Months Ended
Dec. 31, 2016
Dec. 31, 2015
Debt Instrument [Line Items]    
Long-term borrowings $ 8,309,159 $ 7,041,364
Subordinated Notes    
Debt Instrument [Line Items]    
Long-term borrowings 4,821,846 5,540,135
Subordinated Notes | 3.86% Huntington National Bank subordinated notes due 2026    
Debt Instrument [Line Items]    
Long-term borrowings 239,293 0
Subordinated Notes | 3.86% Huntington National Bank subordinated notes due 2026    
Debt Instrument [Line Items]    
Long-term borrowings $ 131,910 136,227
Stated rate 6.67%  
Subordinated Notes | 6.67% Huntington National Bank subordinated notes due 2018    
Debt Instrument [Line Items]    
Long-term borrowings $ 0 103,357
Stated rate 5.59%  
Subordinated Notes | 5.45% Huntington National Bank subordinated notes due 2019    
Debt Instrument [Line Items]    
Long-term borrowings $ 81,155 83,833
Stated rate 5.45%  
Senior Notes | 1.43% Huntington National Bank senior note due 2019    
Debt Instrument [Line Items]    
Long-term borrowings $ 499,445 500,416
Stated rate 2.23%  
Senior Notes | 2.24% Huntington National Bank senior notes due 2018    
Debt Instrument [Line Items]    
Long-term borrowings $ 843,568 841,313
Stated rate 2.24%  
Senior Notes | 2.10% Huntington National Bank senior notes due 2018    
Debt Instrument [Line Items]    
Long-term borrowings $ 747,170 745,894
Stated rate 2.10%  
Senior Notes | 1.75% Huntington National Bank senior notes due 2018    
Debt Instrument [Line Items]    
Long-term borrowings $ 499,732 501,006
Stated rate 1.75%  
Senior Notes | 2.23% Huntington National Bank senior note due 2017    
Debt Instrument [Line Items]    
Long-term borrowings $ 498,448 498,185
Stated rate 2.43%  
Senior Notes | 2.43% Huntington National Bank senior notes due 2020    
Debt Instrument [Line Items]    
Long-term borrowings $ 495,088 495,998
Stated rate 2.97%  
Senior Notes | 2.97% Huntington National Bank senior notes due 2020    
Debt Instrument [Line Items]    
Long-term borrowings $ 499,686 498,678
Stated rate 1.43%  
Senior Notes | 1.42% Huntington National Bank senior notes due 2017 (5)    
Debt Instrument [Line Items]    
Long-term borrowings $ 0 498,360
Stated rate 1.31%  
Senior Notes | 5.04% Huntington National Bank medium-term notes due 2018    
Debt Instrument [Line Items]    
Long-term borrowings $ 0 349,399
Stated rate 1.40%  
Senior Notes | 0.74% Huntington National Bank senior note due 2017    
Debt Instrument [Line Items]    
Long-term borrowings $ 250,000 250,000
Effective rate 0.74%  
Senior Notes | 1.40% Huntington National Bank senior note due 2016    
Debt Instrument [Line Items]    
Long-term borrowings $ 36,351 37,469
Stated rate 5.04%  
Senior Notes | Three-month LIBOR | 0.74% Huntington National Bank senior note due 2017    
Debt Instrument [Line Items]    
Basis spread on variable rate 0.425%  
Federal Home Loan Bank advances    
Debt Instrument [Line Items]    
Long-term borrowings $ 7,540 7,800
Other borrowings    
Debt Instrument [Line Items]    
Long-term borrowings $ 335,158 452,448
Other borrowings | FHLB advances    
Debt Instrument [Line Items]    
Effective rate 3.46%  
Other borrowings | Huntington Technology Finance nonrecourse debt, 3.43% effective interest rate, varying maturities    
Debt Instrument [Line Items]    
Long-term borrowings $ 277,523 301,577
Effective rate 4.21%  
Other borrowings | Huntington Technology Finance ABS Trust 2014 1.70% due 2020    
Debt Instrument [Line Items]    
Long-term borrowings $ 57,494 123,577
Stated rate 1.35%  
Other borrowings | Huntington Technology Finance ABS Trust 2012 1.79% due 2017    
Debt Instrument [Line Items]    
Long-term borrowings $ 0 27,153
Stated rate 1.79%  
Other borrowings | Other    
Debt Instrument [Line Items]    
Long-term borrowings $ 141 141
Parent Company    
Debt Instrument [Line Items]    
Long-term borrowings 3,144,615 1,040,981
Parent Company | Subordinated Notes    
Debt Instrument [Line Items]    
Long-term borrowings 248,156 0
Parent Company | Subordinated Notes | 7.00% Huntington Bancshares Incorporated subordinated notes due 2020    
Debt Instrument [Line Items]    
Long-term borrowings $ 319,857 326,379
Stated rate 7.00%  
Parent Company | Subordinated Notes | Huntington Capital I Trust Preferred 1.03% junior subordinated debentures due 2027    
Debt Instrument [Line Items]    
Long-term borrowings $ 68,720 110,706
Effective rate 1.03%  
Parent Company | Subordinated Notes | Sky Financial Capital Trust IV 1.73% Junior Subordinated Debentures Due 2036    
Debt Instrument [Line Items]    
Long-term borrowings $ 74,320 74,320
Effective rate 1.73%  
Parent Company | Subordinated Notes | Sky Financial Capital Trust III 2.01% junior subordinated debentures due 2036    
Debt Instrument [Line Items]    
Long-term borrowings $ 72,165 72,165
Effective rate 2.01%  
Parent Company | Subordinated Notes | Huntington Capital II Trust Preferred 1.14% junior subordinated debentures due 2028    
Debt Instrument [Line Items]    
Long-term borrowings $ 31,576 54,030
Effective rate 1.14%  
Parent Company | Subordinated Notes | Camco Statutory Trust I 2.95% due 2037    
Debt Instrument [Line Items]    
Long-term borrowings $ 4,244 4,212
Effective rate 2.95%  
Parent Company | Subordinated Notes | Three-month LIBOR | Huntington Capital I Trust Preferred 1.03% junior subordinated debentures due 2027    
Debt Instrument [Line Items]    
Basis spread on variable rate 0.70%  
Parent Company | Subordinated Notes | Three-month LIBOR | Sky Financial Capital Trust IV 1.73% Junior Subordinated Debentures Due 2036    
Debt Instrument [Line Items]    
Basis spread on variable rate 1.40%  
Parent Company | Subordinated Notes | Three-month LIBOR | Sky Financial Capital Trust III 2.01% junior subordinated debentures due 2036    
Debt Instrument [Line Items]    
Basis spread on variable rate 1.40%  
Parent Company | Subordinated Notes | Three-month LIBOR | Huntington Capital II Trust Preferred 1.14% junior subordinated debentures due 2028    
Debt Instrument [Line Items]    
Basis spread on variable rate 0.625%  
Parent Company | Subordinated Notes | Three-month LIBOR | Camco Statutory Trust I 2.95% due 2037    
Debt Instrument [Line Items]    
Basis spread on variable rate 1.33%  
Parent Company | Senior Notes | Huntington Bancshares Incorporated Medium-Term Notes Due 2021, 3.19 Percent    
Debt Instrument [Line Items]    
Long-term borrowings $ 972,625 0
Parent Company | Senior Notes | Huntington Bancshares Incorporated Senior Note due 2022, 2.33 Percent    
Debt Instrument [Line Items]    
Long-term borrowings 953,674 0
Parent Company | Senior Notes | 3.19% Huntington Bancshares Incorporated medium-term notes due 2021    
Debt Instrument [Line Items]    
Long-term borrowings $ 399,278 $ 399,169
Stated rate 2.64%