Fair Value of Assets and Liabilities - Summary Of Book Value And Estimated Fair Value Of Financial Instruments (Details) - USD ($) $ in Millions	Jun. 30, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	$ 60,558	$ 57,417
Short-term financial assets:
Interest-bearing deposits with banks	4,523	1,384
Securities purchased under agreements to resell	190	353
Trading securities	1,059	1,375
Loans held for sale:	789	590
Securities available for sale at fair value	8,600	8,836
Securities held to maturity	1,349	1,371
Derivative assets	728	458
Other Assets Financial Instruments [Abstract]
Total assets	85,071	78,953
Liabilities:
Trading liabilities	174	335
Short Term Financial Liabilities [Abstract]
Securities sold under agreements to repurchase	1,957	1,013
Long-Term Debt, Unclassified [Abstract]
Other long-term borrowings	1,156	1,597
Derivative liabilities	899	929
Total liabilities	76,111	70,406
Fair Value, Inputs, Level 3 | FHLB-Cincinnati Stock
Long-Term Debt, Unclassified [Abstract]
Restricted investments	327	50
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	60,558	57,417
Short-term financial assets:
Interest-bearing deposits with banks	4,523	1,384
Federal funds sold	92	129
Securities purchased under agreements to resell	190	353
Total short-term financial assets	4,805	1,866
Trading securities	1,059	1,375
Loans held for sale:	789	590
Securities available for sale at fair value	8,600	8,836
Securities held to maturity	1,349	1,371
Derivative assets	730	460
Other Assets Financial Instruments [Abstract]
Tax credit investments	583	547
Deferred compensation mutual funds	99	112
Equity, mutual funds, and other	553	275
Total other assets	1,235	934
Total assets	79,125	72,849
Liabilities:
Defined maturity deposits	8,279	2,887
Trading liabilities	174	335
Short Term Financial Liabilities [Abstract]
Federal funds purchased	212	400
Securities sold under agreements to repurchase	1,957	1,013
Other short-term borrowings	4,777	1,093
Total short-term financial liabilities	6,946	2,506
Long-Term Debt, Unclassified [Abstract]
Real estate investment trust-preferred	46	46
Term borrowings—new market tax credit investment	65	66
Secured borrowings	11	3
Junior subordinated debentures	149	148
Other long-term borrowings	885	1,334
Total term borrowings	1,156	1,597
Derivative liabilities	933	958
Total liabilities	17,488	8,283
Reported Value Measurement | Commercial, financial and industrial
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	32,790	31,473
Reported Value Measurement | Commercial Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	13,732	13,082
Reported Value Measurement | Consumer Real Estate
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	13,254	12,053
Reported Value Measurement | Credit card and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	782	809
Reported Value Measurement | Mortgage loans (elected fair value)
Short-term financial assets:
Loans held for sale:	95	51
Reported Value Measurement | USDA & SBA loans - LOCOM
Short-term financial assets:
Loans held for sale:	664	506
Reported Value Measurement | Mortgage loans - LOCOM
Short-term financial assets:
Loans held for sale:	30	33
Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	59,917	56,982
Short-term financial assets:
Interest-bearing deposits with banks	4,523	1,384
Federal funds sold	92	129
Securities purchased under agreements to resell	190	353
Total short-term financial assets	4,805	1,866
Trading securities	1,059	1,375
Loans held for sale:	792	596
Securities available for sale at fair value	8,600	8,836
Securities held to maturity	1,175	1,209
Derivative assets	730	460
Other Assets Financial Instruments [Abstract]
Tax credit investments	575	542
Deferred compensation mutual funds	99	112
Equity, mutual funds, and other	553	275
Total other assets	1,227	929
Total assets	78,305	72,253
Liabilities:
Defined maturity deposits	8,347	2,890
Trading liabilities	174	335
Short Term Financial Liabilities [Abstract]
Federal funds purchased	212	400
Securities sold under agreements to repurchase	1,957	1,013
Other short-term borrowings	4,777	1,093
Total short-term financial liabilities	6,946	2,506
Long-Term Debt, Unclassified [Abstract]
Real estate investment trust-preferred	47	47
Term borrowings—new market tax credit investment	59	59
Secured borrowings	11	3
Junior subordinated debentures	150	150
Other long-term borrowings	793	1,301
Total term borrowings	1,060	1,560
Derivative liabilities	933	958
Total liabilities	17,460	8,249
Unfunded Commitments [Abstract]
Loan commitments	1	1
Standby and other commitments	7	7
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	32,673	31,329
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	13,521	12,909
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	12,935	11,934
Estimate of Fair Value Measurement | Credit card and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	788	810
Estimate of Fair Value Measurement | Mortgage loans (elected fair value)
Short-term financial assets:
Loans held for sale:	95	51
Estimate of Fair Value Measurement | USDA & SBA loans - LOCOM
Short-term financial assets:
Loans held for sale:	667	512
Estimate of Fair Value Measurement | Mortgage loans - LOCOM
Short-term financial assets:
Loans held for sale:	30	33
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	4,523	1,384
Federal funds sold	0	0
Securities purchased under agreements to resell	0	0
Total short-term financial assets	4,523	1,384
Trading securities	0	0
Loans held for sale:	0	0
Securities available for sale at fair value	0	0
Securities held to maturity	0	0
Derivative assets	6	9
Other Assets Financial Instruments [Abstract]
Tax credit investments	0	0
Deferred compensation mutual funds	99	112
Equity, mutual funds, and other	23	22
Total other assets	122	134
Total assets	4,651	1,527
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	4	8
Total liabilities	4	8
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
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 | 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	92	129
Securities purchased under agreements to resell	190	353
Total short-term financial assets	282	482
Trading securities	1,023	1,350
Loans held for sale:	740	541
Securities available for sale at fair value	8,600	8,836
Securities held to maturity	1,175	1,209
Derivative assets	724	451
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	12,544	12,869
Liabilities:
Defined maturity deposits	8,347	2,890
Trading liabilities	174	335
Short Term Financial Liabilities [Abstract]
Federal funds purchased	212	400
Securities sold under agreements to repurchase	1,957	1,013
Other short-term borrowings	4,777	1,093
Total short-term financial liabilities	6,946	2,506
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	793	1,301
Total term borrowings	793	1,301
Derivative liabilities	895	923
Total liabilities	17,155	7,955
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
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:	73	29
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 2 | USDA & SBA loans - LOCOM
Short-term financial assets:
Loans held for sale:	667	512
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	59,917	56,982
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	36	25
Loans held for sale:	52	55
Securities available for sale at fair value	0	0
Securities held to maturity	0	0
Derivative assets	0	0
Other Assets Financial Instruments [Abstract]
Tax credit investments	575	542
Deferred compensation mutual funds	0	0
Equity, mutual funds, and other	530	253
Total other assets	1,105	795
Total assets	61,110	57,857
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	59
Secured borrowings	11	3
Junior subordinated debentures	150	150
Other long-term borrowings	0	0
Total term borrowings	267	259
Derivative liabilities	34	27
Total liabilities	301	286
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	32,673	31,329
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	13,521	12,909
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	12,935	11,934
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 3 | Credit card and other
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	788	810
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 3 | Mortgage loans (elected fair value)
Short-term financial assets:
Loans held for sale:	22	22
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 3 | USDA & SBA loans - LOCOM
Short-term financial assets:
Loans held for sale:	0	0
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 3 | Mortgage loans - LOCOM
Short-term financial assets:
Loans held for sale:	30	33
Contractual Amount
Unfunded Commitments [Abstract]
Loan commitments	25,167	25,953
Standby and other commitments	$ 763	$ 754