Annual report pursuant to Section 13 and 15(d)

BORROWINGS - Schedule of Long-Term Debt and Debt Issuances (Details)

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BORROWINGS - Schedule of Long-Term Debt and Debt Issuances (Details) - USD ($)
$ in Millions
 12 Months Ended
Dec. 31, 2021
Dec. 31, 2020
Debt Instrument [Line Items]    
Long-term debt $ 7,108 $ 8,352
Senior Notes | 0.79% Huntington National Bank senior notes due 2021    
Debt Instrument [Line Items]    
Long-term debt $ 0 298
Effective rate 0.79%  
Senior Notes | 3.33% Huntington National Bank senior notes due 2021    
Debt Instrument [Line Items]    
Long-term debt $ 0 752
Effective rate 3.33%  
Senior Notes | 2.55% Huntington National Bank senior notes due 2022    
Debt Instrument [Line Items]    
Long-term debt $ 703 710
Effective rate 2.55%  
Senior Notes | 3.16% Huntington National Bank senior notes due 2022    
Debt Instrument [Line Items]    
Long-term debt $ 500 511
Effective rate 3.16%  
Senior Notes | 1.83% Huntington National Bank senior notes due 2023    
Debt Instrument [Line Items]    
Long-term debt $ 483 489
Effective rate 1.83%  
Senior Notes | 3.60% Huntington National Bank senior notes due 2023    
Debt Instrument [Line Items]    
Long-term debt $ 748 773
Effective rate 3.60%  
Subordinated Notes    
Debt Instrument [Line Items]    
Long-term debt $ 3,245 3,766
Subordinated Notes | Huntington National Bank subordinated notes due 2022    
Debt Instrument [Line Items]    
Long-term debt $ 113 0
Effective rate 0.64%  
Subordinated Notes | Huntington National Bank subordinated notes due 2025    
Debt Instrument [Line Items]    
Long-term debt $ 142 0
Effective rate 0.96%  
Subordinated Notes | 3.86% Huntington National Bank subordinated notes due 2026    
Debt Instrument [Line Items]    
Long-term debt $ 226 233
Effective rate 3.86%  
Subordinated Notes | Huntington National Bank subordinated notes due 2029    
Debt Instrument [Line Items]    
Long-term debt $ 161 0
Effective rate 3.03%  
Subordinated Notes | Huntington National Bank subordinated notes due 2030    
Debt Instrument [Line Items]    
Long-term debt $ 169 0
Effective rate 3.75%  
Federal Home Loan Bank advances    
Debt Instrument [Line Items]    
Long-term debt $ 215 3
Effective rate 1.04%  
Other borrowings | Huntington Technology Finance nonrecourse debt, 3.15% weighted average interest rate, varying maturities    
Debt Instrument [Line Items]    
Long-term debt $ 287 266
Effective rate 3.15%  
Other borrowings | 2.12% Huntington Preferred Capital II - Class F securities    
Debt Instrument [Line Items]    
Long-term debt $ 75 75
Effective rate 2.09%  
Other borrowings | 2.12% Huntington Preferred Capital II - Class G securities    
Debt Instrument [Line Items]    
Long-term debt $ 50 50
Effective rate 2.09%  
Other borrowings | 2.24% Huntington Preferred Capital II - Class I securities    
Debt Instrument [Line Items]    
Long-term debt $ 50 50
Effective rate 2.21%  
Other borrowings | 2.65% Huntington Preferred Capital II - Class J Securities    
Debt Instrument [Line Items]    
Long-term debt $ 75 0
Parent Company    
Debt Instrument [Line Items]    
Long-term debt 3,111 4,142
Parent Company | Senior Notes | 3.19% Huntington Bancshares Incorporated medium-term notes due 2021    
Debt Instrument [Line Items]    
Long-term debt $ 0 802
Effective rate 3.19%  
Parent Company | Senior Notes | 2.33% Huntington Bancshares Incorporated senior notes due 2022    
Debt Instrument [Line Items]    
Long-term debt $ 0 699
Effective rate 2.33%  
Parent Company | Senior Notes | 2.67% Huntington Bancshares Incorporated senior notes due 2024    
Debt Instrument [Line Items]    
Long-term debt $ 812 838
Effective rate 2.67%  
Parent Company | Senior Notes | 4.05% Huntington Bancshares Incorporated senior notes due 2025    
Debt Instrument [Line Items]    
Long-term debt $ 527 553
Effective rate 4.05%  
Parent Company | Senior Notes | 2.60% Huntington Bancshares Incorporated senior notes due 2030    
Debt Instrument [Line Items]    
Long-term debt $ 744 743
Effective rate 2.60%  
Parent Company | Subordinated Notes | 3.55% Huntington Bancshares Incorporated subordinated notes due 2023    
Debt Instrument [Line Items]    
Long-term debt $ 227 256
Effective rate 3.55%  
Parent Company | Subordinated Notes | Huntington Capital I Trust Preferred 0.94% junior subordinated debentures due 2027    
Debt Instrument [Line Items]    
Long-term debt $ 69 69
Effective rate 0.91%  
Parent Company | 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 0.83%  
Parent Company | 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 1.61%  
Parent Company | 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 1.61%  
Parent Company | Subordinated Notes | Huntington Bancshares Incorporated subordinated notes due 2036    
Debt Instrument [Line Items]    
Long-term debt $ 554 0
Effective rate 2.54%  
Parent Company | Subordinated Notes | Camco Financial Statutory Trust I 1.57% due 2037    
Debt Instrument [Line Items]    
Long-term debt $ 0 $ 4
Effective rate 1.57%  
Parent Company | Subordinated Notes | London Interbank Offered Rate (LIBOR) | Huntington Capital I Trust Preferred 0.94% junior subordinated debentures due 2027    
Debt Instrument [Line Items]    
Basis spread on variable rate 0.70%  
Parent Company | Subordinated Notes | London Interbank Offered Rate (LIBOR) | Huntington Capital II Trust Preferred 0.86% junior subordinated debentures due 2028    
Debt Instrument [Line Items]    
Basis spread on variable rate 0.625%  
Parent Company | Subordinated Notes | London Interbank Offered Rate (LIBOR) | Sky Financial Capital Trust IV 1.64% junior subordinated debentures due 2036    
Debt Instrument [Line Items]    
Basis spread on variable rate 1.40%  
Parent Company | Subordinated Notes | London Interbank Offered Rate (LIBOR) | 2.12% Huntington Preferred Capital II - Class F securities    
Debt Instrument [Line Items]    
Basis spread on variable rate 1.88%  
Parent Company | Subordinated Notes | London Interbank Offered Rate (LIBOR) | 2.24% Huntington Preferred Capital II - Class I securities    
Debt Instrument [Line Items]    
Basis spread on variable rate 2.00%  
Parent Company | Subordinated Notes | Secured Overnight Financing Rate (SOFR) Overnight Index Swap Rate | 2.65% Huntington Preferred Capital II - Class J Securities    
Debt Instrument [Line Items]    
Basis spread on variable rate 2.60%