Annual report pursuant to Section 13 and 15(d)

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

v3.20.4
LONG-TERM DEBT - Schedule of Long-Term Debt and Debt Issuances (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2020
Jan. 28, 2020
Dec. 31, 2019
Debt Instrument [Line Items]      
Long-term debt $ 8,352   $ 9,849
Senior Notes | 2.47% Huntington National Bank senior notes due 2020      
Debt Instrument [Line Items]      
Long-term debt     $ 699
Effective rate     2.47%
Senior Notes | 2.42% Huntington National Bank senior notes due 2020      
Debt Instrument [Line Items]      
Long-term debt     $ 300
Effective rate     2.42%
Senior Notes | 2.43% Huntington National Bank senior notes due 2020      
Debt Instrument [Line Items]      
Long-term debt     $ 500
Effective rate     2.43%
Senior Notes | 2.97% Huntington National Bank senior notes due 2020      
Debt Instrument [Line Items]      
Long-term debt     $ 499
Effective rate     2.97%
Senior Notes | 0.79% Huntington National Bank senior notes due 2021      
Debt Instrument [Line Items]      
Long-term debt $ 298   $ 299
Effective rate 0.79%    
Senior Notes | 3.33% Huntington National Bank senior notes due 2021      
Debt Instrument [Line Items]      
Long-term debt $ 752   759
Effective rate 3.33%    
Senior Notes | 2.55% Huntington National Bank senior notes due 2022      
Debt Instrument [Line Items]      
Long-term debt $ 710   691
Effective rate 2.55%    
Senior Notes | 3.16% Huntington National Bank senior notes due 2022      
Debt Instrument [Line Items]      
Long-term debt $ 511   507
Effective rate 3.16%    
Senior Notes | 1.83% Huntington National Bank senior notes due 2023      
Debt Instrument [Line Items]      
Long-term debt $ 489   $ 0
Effective rate     1.83%
Senior Notes | 3.60% Huntington National Bank senior notes due 2023      
Debt Instrument [Line Items]      
Long-term debt $ 773   $ 778
Effective rate 3.60%    
Subordinated Notes      
Debt Instrument [Line Items]      
Long-term debt $ 3,766   5,263
Subordinated Notes | 3.86% Huntington National Bank subordinated notes due 2026      
Debt Instrument [Line Items]      
Long-term debt $ 233   231
Effective rate 3.86%    
Federal Home Loan Bank advances      
Debt Instrument [Line Items]      
Long-term debt $ 3   5
Effective rate 1.54%    
Other borrowings | Huntington Technology Finance nonrecourse debt, 3.63% weighted average interest rate, varying maturities      
Debt Instrument [Line Items]      
Long-term debt $ 266   312
Effective rate 3.63%    
Other borrowings | 2.12% Huntington Preferred Capital II - Class F securities      
Debt Instrument [Line Items]      
Long-term debt $ 75   74
Effective rate 2.12%    
Other borrowings | 2.12% Huntington Preferred Capital II - Class G securities      
Debt Instrument [Line Items]      
Long-term debt $ 50   50
Effective rate 2.12%    
Other borrowings | 2.24% Huntington Preferred Capital II - Class I securities      
Debt Instrument [Line Items]      
Long-term debt $ 50   50
Effective rate 2.24%    
Parent      
Debt Instrument [Line Items]      
Long-term debt $ 4,142   4,095
Parent | Senior Notes | 3.19% Huntington Bancshares Incorporated medium-term notes due 2021      
Debt Instrument [Line Items]      
Long-term debt $ 802   993
Effective rate 3.19%    
Parent | Senior Notes | 2.33% Huntington Bancshares Incorporated senior notes due 2022      
Debt Instrument [Line Items]      
Long-term debt $ 699   972
Effective rate 2.33%    
Parent | Senior Notes | 2.67% Huntington Bancshares Incorporated senior notes due 2024      
Debt Instrument [Line Items]      
Long-term debt $ 838   798
Effective rate 2.67%    
Parent | Senior Notes | 4.05% Huntington Bancshares Incorporated senior notes due 2025      
Debt Instrument [Line Items]      
Long-term debt $ 553   528
Effective rate 4.05%    
Parent | Senior Notes | 2.60% Huntington Bancshares Incorporated senior notes due 2030      
Debt Instrument [Line Items]      
Long-term debt $ 743   0
Stated rate   2.55%  
Effective rate 2.60%    
Debt face amount   $ 750  
Debt percent of value issued 99.597%    
Parent | Subordinated Notes | 7.00% Huntington Bancshares Incorporated subordinated notes due 2020      
Debt Instrument [Line Items]      
Long-term debt     $ 305
Stated rate     7.00%
Parent | Subordinated Notes | 3.55% Huntington Bancshares Incorporated subordinated notes due 2023      
Debt Instrument [Line Items]      
Long-term debt $ 256   $ 247
Effective rate 3.55%    
Parent | Subordinated Notes | Huntington Capital I Trust Preferred 0.94% junior subordinated debentures due 2027      
Debt Instrument [Line Items]      
Long-term debt $ 69   70
Effective rate 0.94%    
Parent | Subordinated Notes | Huntington Capital II Trust Preferred 0.86% junior subordinated debentures due 2028      
Debt Instrument [Line Items]      
Long-term debt $ 32   32
Effective rate 0.86%    
Parent | Subordinated Notes | Sky Financial Capital Trust III 1.64% junior subordinated debentures due 2036      
Debt Instrument [Line Items]      
Long-term debt $ 72   72
Effective rate 1.64%    
Parent | Subordinated Notes | Sky Financial Capital Trust IV 1.64% junior subordinated debentures due 2036      
Debt Instrument [Line Items]      
Long-term debt $ 74   74
Effective rate 1.64%    
Parent | Subordinated Notes | Camco Financial Statutory Trust I 1.57% due 2037      
Debt Instrument [Line Items]      
Long-term debt $ 4   $ 4
Effective rate 1.57%    
Parent | Subordinated Notes | London Interbank Offered Rate (LIBOR) [Member] | Huntington Capital I Trust Preferred 0.94% junior subordinated debentures due 2027      
Debt Instrument [Line Items]      
Basis spread on variable rate 0.70%    
Parent | Subordinated Notes | London Interbank Offered Rate (LIBOR) [Member] | Huntington Capital II Trust Preferred 0.86% junior subordinated debentures due 2028      
Debt Instrument [Line Items]      
Basis spread on variable rate 0.625%    
Parent | Subordinated Notes | London Interbank Offered Rate (LIBOR) [Member] | Sky Financial Capital Trust IV 1.64% junior subordinated debentures due 2036      
Debt Instrument [Line Items]      
Basis spread on variable rate 1.40%    
Parent | Subordinated Notes | London Interbank Offered Rate (LIBOR) [Member] | Camco Financial Statutory Trust I 1.57% due 2037      
Debt Instrument [Line Items]      
Basis spread on variable rate 1.33%    
Parent | Subordinated Notes | London Interbank Offered Rate (LIBOR) [Member] | 2.42% Huntington National Bank senior notes due 2020      
Debt Instrument [Line Items]      
Basis spread on variable rate 0.51%    
Parent | Subordinated Notes | London Interbank Offered Rate (LIBOR) [Member] | 0.79% Huntington National Bank senior notes due 2021      
Debt Instrument [Line Items]      
Basis spread on variable rate 0.55%    
Parent | Subordinated Notes | London Interbank Offered Rate (LIBOR) [Member] | 2.12% Huntington Preferred Capital II - Class F securities      
Debt Instrument [Line Items]      
Basis spread on variable rate 1.88%    
Parent | Subordinated Notes | London Interbank Offered Rate (LIBOR) [Member] | 2.24% Huntington Preferred Capital II - Class I securities      
Debt Instrument [Line Items]      
Basis spread on variable rate 2.00%    
Bank | Senior Notes | 1.83% Huntington National Bank senior notes due 2023      
Debt Instrument [Line Items]      
Stated rate   1.80%  
Debt face amount   $ 500  
Debt percent of value issued 99.916%