Fair Value of Assets and Liabilities - Summary Of Book Value And Estimated Fair Value Of Financial Instruments (Details) - USD ($) $ in Millions	Mar. 31, 2023	Dec. 31, 2022
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	$ 58,330	$ 57,417
Short-term financial assets:
Interest-bearing deposits with banks	2,488	1,384
Securities Purchased under Agreements to Resell	168	353
Trading securities	1,122	1,375
Loans held for sale:	650	590
Securities available for sale at fair value	8,954	8,836
Securities held to maturity	1,362	1,371
Derivative assets	546	458
Other Assets Financial Instruments [Abstract]
Total assets	80,729	78,953
Liabilities:
Trading liabilities	144	335
Short Term Financial Liabilities [Abstract]
Securities sold under agreements to repurchase	1,174	1,013
Long-Term Debt, Unclassified [Abstract]
Other long-term borrowings	1,605	1,597
Derivative liabilities	698	929
Total liabilities	71,834	70,406
Fair Value, Inputs, Level 3 | FHLB-Cincinnati Stock
Long-Term Debt, Unclassified [Abstract]
Restricted investments	232	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	58,330	57,417
Short-term financial assets:
Interest-bearing deposits with banks	2,488	1,384
Federal funds sold	141	129
Securities Purchased under Agreements to Resell	168	353
Total short-term financial assets	2,797	1,866
Trading securities	1,122	1,375
Loans held for sale:	650	590
Securities available for sale at fair value	8,954	8,836
Securities held to maturity	1,362	1,371
Derivative assets	548	460
Other Assets Financial Instruments [Abstract]
Tax credit investments	545	547
Deferred compensation mutual funds	98	112
Equity, mutual funds, and other	458	275
Total other assets	1,101	934
Total assets	74,864	72,849
Liabilities:
Defined maturity deposits	3,777	2,887
Trading liabilities	144	335
Short Term Financial Liabilities [Abstract]
Federal funds purchased	447	400
Securities sold under agreements to repurchase	1,174	1,013
Other short-term borrowings	4,863	1,093
Total short-term financial liabilities	6,484	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	1,334	1,334
Total term borrowings	1,605	1,597
Derivative liabilities	722	958
Total liabilities	12,732	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	31,847	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	13,248	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	12,459	12,053
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	776	809
Reported Value Measurement | Mortgage loans (elected fair value)
Short-term financial assets:
Loans held for sale:	68	51
Reported Value Measurement | USDA & SBA loans - LOCOM
Short-term financial assets:
Loans held for sale:	551	506
Reported Value Measurement | Mortgage loans - LOCOM
Short-term financial assets:
Loans held for sale:	31	33
Estimate of Fair Value Measurement
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Net loans and leases	58,095	56,982
Short-term financial assets:
Interest-bearing deposits with banks	2,488	1,384
Federal funds sold	141	129
Securities Purchased under Agreements to Resell	168	353
Total short-term financial assets	2,797	1,866
Trading securities	1,122	1,375
Loans held for sale:	654	596
Securities available for sale at fair value	8,954	8,836
Securities held to maturity	1,214	1,209
Derivative assets	548	460
Other Assets Financial Instruments [Abstract]
Tax credit investments	541	542
Deferred compensation mutual funds	98	112
Equity, mutual funds, and other	458	275
Total other assets	1,097	929
Total assets	74,481	72,253
Liabilities:
Defined maturity deposits	3,793	2,890
Trading liabilities	144	335
Short Term Financial Liabilities [Abstract]
Federal funds purchased	447	400
Securities sold under agreements to repurchase	1,174	1,013
Other short-term borrowings	4,863	1,093
Total short-term financial liabilities	6,484	2,506
Long-Term Debt, Unclassified [Abstract]
Real estate investment trust-preferred	47	47
Term borrowings—new market tax credit investment	60	59
Secured borrowings	11	3
Junior subordinated debentures	150	150
Other long-term borrowings	1,300	1,301
Total term borrowings	1,568	1,560
Derivative liabilities	722	958
Total liabilities	12,711	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	31,880	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	13,109	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	12,330	11,934
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	776	810
Estimate of Fair Value Measurement | Mortgage loans (elected fair value)
Short-term financial assets:
Loans held for sale:	68	51
Estimate of Fair Value Measurement | USDA & SBA loans - LOCOM
Short-term financial assets:
Loans held for sale:	555	512
Estimate of Fair Value Measurement | Mortgage loans - LOCOM
Short-term financial assets:
Loans held for sale:	31	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	2,488	1,384
Federal funds sold	0	0
Securities Purchased under Agreements to Resell	0	0
Total short-term financial assets	2,488	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	11	9
Other Assets Financial Instruments [Abstract]
Tax credit investments	0	0
Deferred compensation mutual funds	98	112
Equity, mutual funds, and other	23	22
Total other assets	121	134
Total assets	2,620	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	12	8
Total liabilities	12	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 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 | 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	141	129
Securities Purchased under Agreements to Resell	168	353
Total short-term financial assets	309	482
Trading securities	1,094	1,350
Loans held for sale:	602	541
Securities available for sale at fair value	8,954	8,836
Securities held to maturity	1,214	1,209
Derivative assets	537	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	12,710	12,869
Liabilities:
Defined maturity deposits	3,793	2,890
Trading liabilities	144	335
Short Term Financial Liabilities [Abstract]
Federal funds purchased	447	400
Securities sold under agreements to repurchase	1,174	1,013
Other short-term borrowings	4,863	1,093
Total short-term financial liabilities	6,484	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	1,300	1,301
Total term borrowings	1,300	1,301
Derivative liabilities	689	923
Total liabilities	12,410	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 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:	47	29
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 2 | USDA & SBA loans - LOCOM
Short-term financial assets:
Loans held for sale:	555	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	58,095	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	28	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	541	542
Deferred compensation mutual funds	0	0
Equity, mutual funds, and other	435	253
Total other assets	976	795
Total assets	59,151	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	60	59
Secured borrowings	11	3
Junior subordinated debentures	150	150
Other long-term borrowings	0	0
Total term borrowings	268	259
Derivative liabilities	21	27
Total liabilities	289	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	31,880	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	13,109	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	12,330	11,934
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	776	810
Estimate of Fair Value Measurement | Fair Value, Inputs, Level 3 | Mortgage loans (elected fair value)
Short-term financial assets:
Loans held for sale:	21	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:	31	33
Contractual Amount
Unfunded Commitments [Abstract]
Loan commitments	24,964	25,953
Standby and other commitments	$ 765	$ 754