Fair Value of Assets and Liabilities - Schedule Of Assets And Liabilities Measured At Fair Value On A Recurring Basis (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	$ 1,823	$ 1,601
Loans held-for-sale	193	258
Securities available for sale at fair value	9,242	8,707
Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Loans held-for-sale	193	258
Securities available for sale at fair value	9,242	8,707
Total other assets	366	474
Total assets	11,624	11,040
Total other liabilities	447	128
Total liabilities	960	554
Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Loans held-for-sale	0	0
Securities available for sale at fair value	0	0
Total other assets	231	162
Total assets	231	162
Total other liabilities	70	11
Total liabilities	70	11
Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Loans held-for-sale	161	230
Securities available for sale at fair value	9,242	8,707
Total other assets	135	312
Total assets	11,349	10,812
Total other liabilities	359	94
Total liabilities	872	520
Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Loans held-for-sale	32	28
Securities available for sale at fair value	0	0
Total other assets	0	0
Total assets	44	66
Total other liabilities	18	23
Total liabilities	18	23
Deferred compensation mutual funds | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	123	125
Deferred compensation mutual funds | Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	123	125
Deferred compensation mutual funds | Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0	0
Deferred compensation mutual funds | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0	0
Equity, mutual funds, and other | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	23	25
Equity, mutual funds, and other | Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	23	25
Equity, mutual funds, and other | Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0	0
Equity, mutual funds, and other | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0	0
Derivatives, forwards and futures | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	85	12
Total other liabilities	70	11
Derivatives, forwards and futures | Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	85	12
Total other liabilities	70	11
Derivatives, forwards and futures | Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0	0
Total other liabilities	0	0
Derivatives, forwards and futures | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0	0
Total other liabilities	0	0
Derivatives, interest rate contracts | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	134	311
Total other liabilities	358	93
Derivatives, interest rate contracts | Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0	0
Total other liabilities	0	0
Derivatives, interest rate contracts | Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	134	311
Total other liabilities	358	93
Derivatives, interest rate contracts | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0	0
Total other liabilities	0	0
Derivatives, other | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	1	1
Total other liabilities	19	24
Derivatives, other | Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0	0
Total other liabilities	0	0
Derivatives, other | Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	1	1
Total other liabilities	1	1
Derivatives, other | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Total other assets	0	0
Total other liabilities	18	23
Government agency issued MBS | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale at fair value	5,046	5,055
Government agency issued MBS | Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale at fair value	0	0
Government agency issued MBS | Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale at fair value	5,046	5,055
Government agency issued MBS | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale at fair value	0	0
Government agency issued CMO | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale at fair value	2,715	2,257
Government agency issued CMO | Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
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]
Securities available for sale at fair value	2,715	2,257
Government agency issued CMO | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
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]
Securities available for sale at fair value	936	850
Other U.S. government agencies | Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale at fair value	0	0
Other U.S. government agencies | Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale at fair value	936	850
Other U.S. government agencies | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale at fair value	0	0
States and municipalities | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale at fair value	545	545
States and municipalities | Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
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]
Securities available for sale at fair value	545	545
States and municipalities | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Securities available for sale at fair value	0	0
Specialty Banking | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	1,823	1,601
Total trading liabilities	513	426
Specialty Banking | Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0	0
Total trading liabilities	0	0
Specialty Banking | Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	1,811	1,563
Total trading liabilities	513	426
Specialty Banking | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	12	38
Total trading liabilities	0	0
Specialty Banking | U.S. treasuries | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	65	85
Total trading liabilities	440	334
Specialty Banking | 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
Specialty Banking | U.S. treasuries | Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	65	85
Total trading liabilities	440	334
Specialty Banking | 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
Specialty Banking | Government agency issued MBS | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	363	464
Total trading liabilities		1
Specialty Banking | Government agency issued MBS | Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0	0
Total trading liabilities		0
Specialty Banking | Government agency issued MBS | Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	363	464
Total trading liabilities		1
Specialty Banking | Government agency issued MBS | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0	0
Total trading liabilities		0
Specialty Banking | Government agency issued CMO | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	315	62
Specialty Banking | Government agency issued CMO | Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0	0
Specialty Banking | Government agency issued CMO | Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	315	62
Specialty Banking | Government agency issued CMO | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0	0
Specialty Banking | Other U.S. government agencies | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	274	276
Specialty Banking | Other U.S. government agencies | Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0	0
Specialty Banking | Other U.S. government agencies | Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	274	276
Specialty Banking | Other U.S. government agencies | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0	0
Specialty Banking | States and municipalities | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	13	34
Specialty Banking | States and municipalities | Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0	0
Specialty Banking | States and municipalities | Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	13	34
Specialty Banking | States and municipalities | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0	0
Specialty Banking | Corporate and other debt | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	781	642
Total trading liabilities	73	91
Specialty Banking | 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
Specialty Banking | Corporate and other debt | Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	781	642
Total trading liabilities	73	91
Specialty Banking | 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
Specialty Banking | Interest- only strips | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	12	38
Specialty Banking | Interest- only strips | Level 1 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0	0
Specialty Banking | Interest- only strips | Level 2 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	0	0
Specialty Banking | Interest- only strips | Level 3 | Recurring
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation [Line Items]
Trading securities	$ 12	$ 38