Fair Value of Assets and Liabilities - Summary Of Book Value And Estimated Fair Value Of Financial Instruments (Details) - USD ($) $ in Millions	Sep. 30, 2022	Dec. 31, 2021
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	$ 56,690	$ 54,189
Short-term financial assets:
Interest-bearing deposits with banks	3,241	14,907
Securities Purchased under Agreements to Resell	492	488
Trading securities	1,421	1,601
Loans held for sale:	680	1,172
Securities available-for-sale	8,718	8,707
Securities held to maturity	1,385	712
Derivative assets	311	323
Other Assets Financial Instruments [Abstract]
Total assets	80,299	89,092
Liabilities:
Trading liabilities	383	426
Short Term Financial Liabilities [Abstract]
Securities sold under agreements to repurchase	658	1,247
Long-Term Debt, Unclassified [Abstract]
Other long term borrowings	1,597	1,590
Derivative liabilities	1,027	103
Total liabilities	72,016	80,598
Fair Value, Inputs, Level 3 | FHLB-Cincinnati Stock
Long-Term Debt, Unclassified [Abstract]
Restricted investments	26	29
Fair Value, Inputs, Level 3 | FRB Stock
Long-Term Debt, Unclassified [Abstract]
Restricted investments	203	203
Reported Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	56,690	54,189
Short-term financial assets:
Interest-bearing deposits with banks	3,241	14,907
Federal funds sold	198	153
Securities Purchased under Agreements to Resell	492	488
Total short-term financial assets	3,931	15,548
Trading securities	1,421	1,601
Loans held for sale:	680	1,172
Securities available-for-sale	8,718	8,707
Securities held to maturity	1,385	712
Derivative assets	318	324
Other Assets Financial Instruments [Abstract]
Tax credit investments	530	456
Deferred compensation mutual funds	106	125
Equity, mutual funds, and other	251	257
Total other assets	887	838
Total assets	74,030	83,091
Liabilities:
Defined maturity deposits	2,671	3,500
Trading liabilities	383	426
Short Term Financial Liabilities [Abstract]
Federal funds purchased	496	775
Securities sold under agreements to repurchase	657	1,247
Other short-term borrowings	263	102
Total short-term financial liabilities	1,416	2,124
Long-Term Debt, Unclassified [Abstract]
Real estate investment trust-preferred	46	46
Term borrowings—new market tax credit investment	66	59
Secured borrowings	4	6
Junior subordinated debentures	148	148
Other long term borrowings	1,333	1,331
Total term borrowings	1,597	1,590
Derivative liabilities	1,049	128
Total liabilities	7,116	7,768
Reported Value Measurement | Commercial, financial and industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	31,325	30,734
Reported Value Measurement | Commercial Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	12,873	11,955
Reported Value Measurement | Consumer Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	11,671	10,609
Reported Value Measurement | Credit Card And Other Portfolio Segment [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	821	891
Reported Value Measurement | Mortgage loans (elected fair value)
Short-term financial assets:
Loans held for sale:	89	258
Reported Value Measurement | USDA & SBA loans - LOCOM
Short-term financial assets:
Loans held for sale:	557	853
Reported Value Measurement | Other loans - LOCOM
Short-term financial assets:
Loans held for sale:		24
Reported Value Measurement | Mortgage loans - LOCOM
Short-term financial assets:
Loans held for sale:	34	37
Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	56,194	55,023
Short-term financial assets:
Interest-bearing deposits with banks	3,241	14,907
Federal funds sold	198	153
Securities Purchased under Agreements to Resell	492	488
Total short-term financial assets	3,931	15,548
Trading securities	1,421	1,601
Loans held for sale:	682	1,175
Securities available-for-sale	8,718	8,707
Securities held to maturity	1,222	705
Derivative assets	318	324
Other Assets Financial Instruments [Abstract]
Tax credit investments	530	450
Deferred compensation mutual funds	106	125
Equity, mutual funds, and other	251	257
Total other assets	887	832
Total assets	73,373	83,915
Liabilities:
Defined maturity deposits	2,668	3,524
Trading liabilities	383	426
Short Term Financial Liabilities [Abstract]
Federal funds purchased	496	775
Securities sold under agreements to repurchase	657	1,247
Other short-term borrowings	263	102
Total short-term financial liabilities	1,416	2,124
Long-Term Debt, Unclassified [Abstract]
Real estate investment trust-preferred	47	47
Term borrowings—new market tax credit investment	59	58
Secured borrowings	4	6
Junior subordinated debentures	150	150
Other long term borrowings	1,331	1,452
Total term borrowings	1,591	1,713
Derivative liabilities	1,049	128
Total liabilities	7,107	7,915
Unfunded Commitments [Abstract]
Loan commitments	1	1
Standby and other commitments	7	6
Estimate of Fair Value Measurement | Commercial, financial and industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	31,084	31,020
Estimate of Fair Value Measurement | Commercial Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	12,735	11,986
Estimate of Fair Value Measurement | Consumer Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	11,550	11,111
Estimate of Fair Value Measurement | Credit Card And Other Portfolio Segment [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	825	906
Estimate of Fair Value Measurement | Mortgage loans (elected fair value)
Short-term financial assets:
Loans held for sale:	89	258
Estimate of Fair Value Measurement | USDA & SBA loans - LOCOM
Short-term financial assets:
Loans held for sale:	559	856
Estimate of Fair Value Measurement | Other loans - LOCOM
Short-term financial assets:
Loans held for sale:		24
Estimate of Fair Value Measurement | Mortgage loans - LOCOM
Short-term financial assets:
Loans held for sale:	34	37
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 1
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	0	0
Short-term financial assets:
Interest-bearing deposits with banks	3,241	14,907
Federal funds sold	0	0
Securities Purchased under Agreements to Resell	0	0
Total short-term financial assets	3,241	14,907
Trading securities	0	0
Loans held for sale:	0	0
Securities available-for-sale	0	0
Securities held to maturity	0	0
Derivative assets	49	12
Other Assets Financial Instruments [Abstract]
Tax credit investments	0	0
Deferred compensation mutual funds	106	125
Equity, mutual funds, and other	22	25
Total other assets	128	150
Total assets	3,418	15,069
Liabilities:
Defined maturity deposits	0	0
Trading liabilities	0	0
Short Term Financial Liabilities [Abstract]
Federal funds purchased	0	0
Securities sold under agreements to repurchase	0	0
Other short-term borrowings	0	0
Total short-term financial liabilities	0	0
Long-Term Debt, Unclassified [Abstract]
Real estate investment trust-preferred	0	0
Term borrowings—new market tax credit investment	0	0
Secured borrowings	0	0
Junior subordinated debentures	0	0
Other long term borrowings	0	0
Total term borrowings	0	0
Derivative liabilities	39	11
Total liabilities	39	11
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 1 | Commercial, financial and industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	0	0
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 1 | Commercial Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	0	0
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 1 | Consumer Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	0	0
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 1 | Credit Card And Other Portfolio Segment [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	0	0
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 1 | Mortgage loans (elected fair value)
Short-term financial assets:
Loans held for sale:	0	0
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 1 | USDA & SBA loans - LOCOM
Short-term financial assets:
Loans held for sale:	0	0
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 1 | Other loans - LOCOM
Short-term financial assets:
Loans held for sale:		0
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 1 | Mortgage loans - LOCOM
Short-term financial assets:
Loans held for sale:	0	0
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 2
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	0	0
Short-term financial assets:
Interest-bearing deposits with banks	0	0
Federal funds sold	198	153
Securities Purchased under Agreements to Resell	492	488
Total short-term financial assets	690	641
Trading securities	1,398	1,563
Loans held for sale:	628	1,109
Securities available-for-sale	8,718	8,707
Securities held to maturity	1,222	705
Derivative assets	269	312
Other Assets Financial Instruments [Abstract]
Tax credit investments	0	0
Deferred compensation mutual funds	0	0
Equity, mutual funds, and other	0	0
Total other assets	0	0
Total assets	12,925	13,037
Liabilities:
Defined maturity deposits	2,668	3,524
Trading liabilities	383	426
Short Term Financial Liabilities [Abstract]
Federal funds purchased	496	775
Securities sold under agreements to repurchase	657	1,247
Other short-term borrowings	263	102
Total short-term financial liabilities	1,416	2,124
Long-Term Debt, Unclassified [Abstract]
Real estate investment trust-preferred	0	0
Term borrowings—new market tax credit investment	0	0
Secured borrowings	0	0
Junior subordinated debentures	0	0
Other long term borrowings	1,331	1,452
Total term borrowings	1,331	1,452
Derivative liabilities	990	94
Total liabilities	6,788	7,620
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 2 | Commercial, financial and industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	0	0
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 2 | Commercial Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	0	0
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 2 | Consumer Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	0	0
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 2 | Credit Card And Other Portfolio Segment [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	0	0
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 2 | Mortgage loans (elected fair value)
Short-term financial assets:
Loans held for sale:	69	230
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 2 | USDA & SBA loans - LOCOM
Short-term financial assets:
Loans held for sale:	559	855
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 2 | Other loans - LOCOM
Short-term financial assets:
Loans held for sale:		24
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 2 | Mortgage loans - LOCOM
Short-term financial assets:
Loans held for sale:	0	0
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 3
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	56,194	55,023
Short-term financial assets:
Interest-bearing deposits with banks	0	0
Federal funds sold	0	0
Securities Purchased under Agreements to Resell	0	0
Total short-term financial assets	0	0
Trading securities	23	38
Loans held for sale:	54	66
Securities available-for-sale	0	0
Securities held to maturity	0	0
Derivative assets	0	0
Other Assets Financial Instruments [Abstract]
Tax credit investments	530	450
Deferred compensation mutual funds	0	0
Equity, mutual funds, and other	229	232
Total other assets	759	682
Total assets	57,030	55,809
Liabilities:
Defined maturity deposits	0	0
Trading liabilities	0	0
Short Term Financial Liabilities [Abstract]
Federal funds purchased	0	0
Securities sold under agreements to repurchase	0	0
Other short-term borrowings	0	0
Total short-term financial liabilities	0	0
Long-Term Debt, Unclassified [Abstract]
Real estate investment trust-preferred	47	47
Term borrowings—new market tax credit investment	59	58
Secured borrowings	4	6
Junior subordinated debentures	150	150
Other long term borrowings	0	0
Total term borrowings	260	261
Derivative liabilities	20	23
Total liabilities	280	284
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 3 | Commercial, financial and industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	31,084	31,020
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 3 | Commercial Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	12,735	11,986
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 3 | Consumer Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	11,550	11,111
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 3 | Credit Card And Other Portfolio Segment [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	825	906
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 3 | Mortgage loans (elected fair value)
Short-term financial assets:
Loans held for sale:	20	28
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 3 | USDA & SBA loans - LOCOM
Short-term financial assets:
Loans held for sale:	0	1
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 3 | Other loans - LOCOM
Short-term financial assets:
Loans held for sale:		0
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 3 | Mortgage loans - LOCOM
Short-term financial assets:
Loans held for sale:	34	37
Contractual Amount
Unfunded Commitments [Abstract]
Loan commitments	26,747	24,229
Standby and other commitments	$ 716	$ 810