Fair Value (Reconciliation of Recurring Fair Value Measurements) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2025	Mar. 31, 2024
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Unrealized gains/losses for the period on assets held on Consolidated Balance Sheet
Fair Value, Recurring | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	$ 7,431	7,448
Included in Earnings	11	187
Included in other comprehensive income	8	(5)
Purchases	254	121
Sales	(110)	(6)
Issuances	16	8
Settlements	(188)	(192)
Transfers into Level 3	4	2
Transfers out of Level 3	(5)	(8)
Ending balance	7,421	7,555
Unrealized gains/losses for the period on assets held on Consolidated Balance Sheet	(13)	185
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	337	398
Included in Earnings	47	(12)
Included in other comprehensive income	0	0
Purchases	0	0
Sales	0	0
Issuances	5	16
Settlements	(86)	(91)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	303	311
Unrealized gains/losses for the period on liabilities held on Consolidated Balance Sheet	45	11
Fair Value Additional Information [Abstract]
Net gains (losses) included in earnings (realized and unrealized) relating to Level 3 assets and liabilities	(36)	199
Net unrealized gains (losses) relating to Level 3 assets and liabilities	(58)	174
Fair Value, Recurring | Level 3 | Other borrowed funds
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	10	9
Included in Earnings	0	0
Included in other comprehensive income	0	0
Purchases	0	0
Sales	0	0
Issuances	5	3
Settlements	(2)	(3)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	13	9
Unrealized gains/losses for the period on liabilities held on Consolidated Balance Sheet	0	0
Fair Value, Recurring | Level 3 | Financial derivatives
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	150	152
Included in Earnings	37	8
Included in other comprehensive income	0	0
Purchases	0	0
Sales	0	0
Issuances	0	0
Settlements	(26)	(47)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	161	113
Unrealized gains/losses for the period on liabilities held on Consolidated Balance Sheet	38	9
Fair Value, Recurring | Level 3 | Other liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	177	237
Included in Earnings	10	(20)
Included in other comprehensive income	0	0
Purchases	0	0
Sales	0	0
Issuances	0	13
Settlements	(58)	(41)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	129	189
Unrealized gains/losses for the period on liabilities held on Consolidated Balance Sheet	7	2
Loans held for sale | Fair Value, Recurring | Level 3 | Residential mortgage loans held for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	68	103
Included in Earnings	0	(1)
Included in other comprehensive income	0	0
Purchases	41	2
Sales	0	0
Issuances	0	0
Settlements	(4)	(2)
Transfers into Level 3	4	2
Transfers out of Level 3	(5)	(6)
Ending balance	104	98
Unrealized gains/losses for the period on assets held on Consolidated Balance Sheet	0	(1)
Loans held for sale | Fair Value, Recurring | Level 3 | Commercial mortgage loans held for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	4	11
Included in Earnings	0	0
Included in other comprehensive income	0	0
Purchases	0	0
Sales	0	0
Issuances	0	0
Settlements	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	4	11
Unrealized gains/losses for the period on assets held on Consolidated Balance Sheet	0	0
Securities available-for-sale | Fair Value, Recurring | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	853	956
Included in Earnings	0	1
Included in other comprehensive income	8	(5)
Purchases	0	0
Sales	0	0
Issuances	0	0
Settlements	(20)	(28)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	841	924
Unrealized gains/losses for the period on assets held on Consolidated Balance Sheet	(3)	(2)
Residential mortgage- backed non-agency | Fair Value, Recurring | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	603	696
Included in Earnings	2	3
Included in other comprehensive income	8	(6)
Purchases	0	0
Sales	0	0
Issuances	0	0
Settlements	(17)	(25)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	596	668
Unrealized gains/losses for the period on assets held on Consolidated Balance Sheet	0	0
Commercial mortgage- backed non-agency | Fair Value, Recurring | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	103	103
Included in Earnings	(3)	0
Included in other comprehensive income	(1)	0
Purchases	0	0
Sales	0	0
Issuances	0	0
Settlements	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	99	103
Unrealized gains/losses for the period on assets held on Consolidated Balance Sheet	(3)	0
Asset-backed | Fair Value, Recurring | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	93	102
Included in Earnings	1	0
Included in other comprehensive income	1	0
Purchases	0	0
Sales	0	0
Issuances	0	0
Settlements	(3)	(2)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	92	100
Unrealized gains/losses for the period on assets held on Consolidated Balance Sheet	0	0
Other | Fair Value, Recurring | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	54	55
Included in Earnings	0	(2)
Included in other comprehensive income	0	1
Purchases	0	0
Sales	0	0
Issuances	0	0
Settlements	0	(1)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	54	53
Unrealized gains/losses for the period on assets held on Consolidated Balance Sheet	0	(2)
Loans | Fair Value, Recurring | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	670	726
Included in Earnings	5	4
Included in other comprehensive income	0	0
Purchases	7	5
Sales	0	0
Issuances	0	0
Settlements	(19)	(20)
Transfers into Level 3	0	0
Transfers out of Level 3	0	(2)
Ending balance	663	713
Unrealized gains/losses for the period on assets held on Consolidated Balance Sheet	5	5
Equity investments | Fair Value, Recurring | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	2,111	1,952
Included in Earnings	46	(5)
Included in other comprehensive income	0	0
Purchases	176	89
Sales	(110)	(6)
Issuances	0	0
Settlements	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	2,223	2,030
Unrealized gains/losses for the period on assets held on Consolidated Balance Sheet	25	(5)
Mortgage Servicing Rights | Fair Value, Recurring | Level 3 | Residential mortgage loans held for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	2,626	2,654
Included in Earnings	(51)	72
Included in other comprehensive income	0	0
Purchases	1	13
Sales	0	0
Issuances	7	5
Settlements	(60)	(57)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	2,523	2,687
Unrealized gains/losses for the period on assets held on Consolidated Balance Sheet	(51)	72
Mortgage Servicing Rights | Fair Value, Recurring | Level 3 | Commercial mortgage loans held for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	1,085	1,032
Included in Earnings	(2)	107
Included in other comprehensive income	0	0
Purchases	27	12
Sales	0	0
Issuances	9	3
Settlements	(78)	(79)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	1,041	1,075
Unrealized gains/losses for the period on assets held on Consolidated Balance Sheet	(2)	107
Financial derivatives | Fair Value, Recurring | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	4	6
Included in Earnings	13	9
Included in other comprehensive income	0	0
Purchases	0	0
Sales	0	0
Issuances	0	0
Settlements	(7)	(6)
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	10	9
Unrealized gains/losses for the period on assets held on Consolidated Balance Sheet	13	9
Other assets | Fair Value, Recurring | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning balance	10	8
Included in Earnings	0	0
Included in other comprehensive income	0	0
Purchases	2	0
Sales	0	0
Issuances	0	0
Settlements	0	0
Transfers into Level 3	0	0
Transfers out of Level 3	0	0
Ending balance	12	8
Unrealized gains/losses for the period on assets held on Consolidated Balance Sheet	$ 0	$ 0