Fair Value of Assets and Liabilities - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	$ 1,387	$ 1,412
Loans held-for-sale	85	68
Securities available for sale at fair value	7,896	8,391
Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	1,387	1,412
Loans held-for-sale	85	68
Securities available for sale at fair value	7,896	8,391
Total other assets	677	713
Total assets	10,045	10,584
Total trading liabilities	550	509
Total other liabilities	671	699
Total liabilities	1,221	1,208
Recurring | Deferred compensation mutual funds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	111	102
Recurring | Equity, mutual funds, and other
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	35	34
Recurring | Derivatives, forwards and futures
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	8	9
Total other liabilities	6	10
Recurring | Derivatives, interest rate contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	522	568
Total other liabilities	649	666
Recurring | Derivatives, other
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	1
Total other liabilities	16	23
Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	0	0
Loans held-for-sale	0	0
Securities available for sale at fair value	0	0
Total other assets	154	145
Total assets	154	145
Total trading liabilities	0	0
Total other liabilities	6	10
Total liabilities	6	10
Level 1 | Recurring | Deferred compensation mutual funds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	111	102
Level 1 | Recurring | Equity, mutual funds, and other
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	35	34
Level 1 | Recurring | Derivatives, forwards and futures
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	8	9
Total other liabilities	6	10
Level 1 | Recurring | Derivatives, interest rate contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0	0
Total other liabilities	0	0
Level 1 | Recurring | Derivatives, other
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0
Total other liabilities	0	0
Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	1,364	1,399
Loans held-for-sale	69	42
Securities available for sale at fair value	7,896	8,391
Total other assets	523	568
Total assets	9,852	10,400
Total trading liabilities	550	509
Total other liabilities	650	666
Total liabilities	1,200	1,175
Level 2 | Recurring | Deferred compensation mutual funds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0	0
Level 2 | Recurring | Equity, mutual funds, and other
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0	0
Level 2 | Recurring | Derivatives, forwards and futures
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0	0
Total other liabilities	0	0
Level 2 | Recurring | Derivatives, interest rate contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	522	568
Total other liabilities	649	666
Level 2 | Recurring | Derivatives, other
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	1
Total other liabilities	1	0
Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	23	13
Loans held-for-sale	16	26
Securities available for sale at fair value	0	0
Total other assets	0	0
Total assets	39	39
Total trading liabilities	0	0
Total other liabilities	15	23
Total liabilities	15	23
Level 3 | Recurring | Deferred compensation mutual funds
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0	0
Level 3 | Recurring | Equity, mutual funds, and other
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0	0
Level 3 | Recurring | Derivatives, forwards and futures
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0	0
Total other liabilities	0	0
Level 3 | Recurring | Derivatives, interest rate contracts
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0	0
Total other liabilities	0	0
Level 3 | Recurring | Derivatives, other
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0
Total other liabilities	15	23
U.S. treasuries | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	3	3
Total trading liabilities	440	426
U.S. treasuries | Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	0	0
Total trading liabilities	0	0
U.S. treasuries | Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	3	3
Total trading liabilities	440	426
U.S. treasuries | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	0	0
Total trading liabilities	0	0
Government agency issued MBS | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	98	114
Securities available for sale at fair value	3,702	4,484
Total trading liabilities		1
Government agency issued MBS | Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	0	0
Securities available for sale at fair value	0	0
Total trading liabilities		0
Government agency issued MBS | Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	98	114
Securities available for sale at fair value	3,702	4,484
Total trading liabilities		1
Government agency issued MBS | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	0	0
Securities available for sale at fair value	0	0
Total trading liabilities		0
Government agency issued CMO | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	180	336
Securities available for sale at fair value	2,767	2,146
Government agency issued CMO | Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	0	0
Securities available for sale at fair value	0	0
Government agency issued CMO | Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	180	336
Securities available for sale at fair value	2,767	2,146
Government agency issued CMO | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	0	0
Securities available for sale at fair value	0	0
Other U.S. government agencies | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	252	152
Securities available for sale at fair value	1,073	1,172
Total trading liabilities	7
Other U.S. government agencies | Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	0	0
Securities available for sale at fair value	0	0
Total trading liabilities	0
Other U.S. government agencies | Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	252	152
Securities available for sale at fair value	1,073	1,172
Total trading liabilities	7
Other U.S. government agencies | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	0	0
Securities available for sale at fair value	0	0
Total trading liabilities	0
States and municipalities | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	64	17
Securities available for sale at fair value	354	589
States and municipalities | Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	0	0
Securities available for sale at fair value	0	0
States and municipalities | Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	64	17
Securities available for sale at fair value	354	589
States and municipalities | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	0	0
Securities available for sale at fair value	0	0
Corporate and other debt | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	767	777
Total trading liabilities	103	82
Corporate and other debt | Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	0	0
Total trading liabilities	0	0
Corporate and other debt | Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	767	777
Total trading liabilities	103	82
Corporate and other debt | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	0	0
Total trading liabilities	0	0
SBA interest-only strips | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	23	13
SBA interest-only strips | Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	0	0
SBA interest-only strips | Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	0	0
SBA interest-only strips | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities:	$ 23	$ 13