Fair Value (Reconciliation ofLevel 3 Assets and Liabilities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022
Fair Value Additional Information [Abstract]
Fair Value, Liability, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Interest and Dividend Income, Operating, Total noninterest income
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Interest and Dividend Income, Operating, Total noninterest income	Interest and Dividend Income, Operating, Total noninterest income
Fair Value, Asset, Recurring Basis, Unobservable Input Reconciliation, Asset, Gain (Loss), Statement of Other Comprehensive Income or Comprehensive Income [Extensible Enumeration]	Total noninterest income
Fair Value, Asset, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Total noninterest income
Fair Value, Liability, Recurring Basis, Still Held, Unrealized Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]		Total noninterest income
Fair Value, Measurements, Recurring | Level 3
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 7,252	$ 5,882
Included in Earnings	464	1,457
Included in Other comprehensive income (b)	(7)	(126)
Purchases	1,335	1,529
Sales	(734)	(816)
Issuances	73	119
Settlements	(876)	(896)
Transfers into Level 3	123	163
Transfers out of Level 3	(182)	(60)
Ending Balance	7,448	7,252
Unrealized gains (losses) on assets held on Consolidated Balance Sheet	404	1,250
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	421	463
Included in Earnings	322	126
Purchases		32
Sales	5	14
Issuances	455	883
Settlements	(805)	(1,097)
Ending Balance	398	421
Unrealized gains or (losses) on liabilities held on Consolidated Balance Sheet	313	128
Fair Value Additional Information [Abstract]
Net gains (losses) included in earnings (realized and unrealized) relating to Level 3 assets and liabilities	142	1,331
Net unrealized gains (losses) relating to Level 3 assets and liabilities	91	1,122
Fair Value, Measurements, Recurring | Level 3 | Residential mortgage-backed Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	819	1,097
Included in Earnings	15	22
Included in Other comprehensive income (b)	(11)	(108)
Settlements	(127)	(192)
Ending Balance	696	819
Fair Value, Measurements, Recurring | Level 3 | Commercial Mortgage-Backed Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	3	3
Included in Other comprehensive income (b)	8
Transfers into Level 3	92
Ending Balance	103	3
Fair Value, Measurements, Recurring | Level 3 | Asset-backed
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	124	163
Included in Earnings	1	2
Included in Other comprehensive income (b)	(1)	(18)
Settlements	(22)	(23)
Ending Balance	102	124
Fair Value, Measurements, Recurring | Level 3 | Other debt
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	55	69
Included in Earnings	(1)
Included in Other comprehensive income (b)	(3)
Purchases	6	6
Settlements	(5)	(20)
Transfers into Level 3	3
Ending Balance	55	55
Fair Value, Measurements, Recurring | Level 3 | Loans Held For Sale | Residential Mortgages
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	243	81
Included in Earnings	1	(5)
Purchases	15	226
Sales	(131)	(34)
Settlements	(10)	(13)
Transfers into Level 3	7	29
Transfers out of Level 3	(22)	(41)
Ending Balance	103	243
Unrealized gains (losses) on assets held on Consolidated Balance Sheet	1	(5)
Fair Value, Measurements, Recurring | Level 3 | Loans Held For Sale | Commercial Mortgages
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	33	49
Included in Earnings	1	(6)
Sales
Settlements	(23)	(10)
Ending Balance	11	33
Unrealized gains (losses) on assets held on Consolidated Balance Sheet		(6)
Fair Value, Measurements, Recurring | Level 3 | Debt Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1,001	1,332
Included in Earnings	15	24
Included in Other comprehensive income (b)	(7)	(126)
Purchases	6	6
Settlements	(154)	(235)
Transfers into Level 3	95
Ending Balance	956	1,001
Fair Value, Measurements, Recurring | Level 3 | Loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	769	884
Included in Earnings	15	23
Purchases	47	55
Sales	(2)	(10)
Settlements	(98)	(164)
Transfers into Level 3	21
Transfers out of Level 3	(26)	(19)
Ending Balance	726	769
Unrealized gains (losses) on assets held on Consolidated Balance Sheet	15	23
Fair Value, Measurements, Recurring | Level 3 | Equity investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1,778	1,680
Included in Earnings	140	445
Purchases	768	291
Sales	(600)	(772)
Transfers into Level 3		134
Transfers out of Level 3	(134)
Ending Balance	1,952	1,778
Unrealized gains (losses) on assets held on Consolidated Balance Sheet	92	237
Fair Value, Measurements, Recurring | Level 3 | Mortgage Servicing Rights | Residential Mortgages
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	2,310	1,078
Included in Earnings	115	509
Purchases	444	897
Sales	(1)
Issuances	23	57
Settlements	(237)	(231)
Ending Balance	2,654	2,310
Unrealized gains (losses) on assets held on Consolidated Balance Sheet	115	509
Fair Value, Measurements, Recurring | Level 3 | Mortgage Servicing Rights | Commercial Mortgages
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1,113	740
Included in Earnings	157	473
Purchases	44	46
Issuances	50	62
Settlements	(332)	(208)
Ending Balance	1,032	1,113
Unrealized gains (losses) on assets held on Consolidated Balance Sheet	157	473
Fair Value, Measurements, Recurring | Level 3 | Financial derivatives
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	5	38
Included in Earnings	19	(6)
Purchases	4	8
Settlements	(22)	(35)
Ending Balance	6	5
Unrealized gains (losses) on assets held on Consolidated Balance Sheet	24	19
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	123	285
Included in Earnings	266	49
Sales	5	14
Settlements	(242)	(225)
Ending Balance	152	123
Unrealized gains or (losses) on liabilities held on Consolidated Balance Sheet	272	62
Fair Value, Measurements, Recurring | Level 3 | Other borrowed funds
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	4	3
Issuances	13	7
Settlements	(8)	(6)
Ending Balance	9	4
Fair Value, Measurements, Recurring | Level 3 | Other liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	294	175
Included in Earnings	56	77
Purchases		32
Issuances	442	876
Settlements	(555)	(866)
Ending Balance	237	294
Unrealized gains or (losses) on liabilities held on Consolidated Balance Sheet	41	$ 66
Fair Value, Measurements, Recurring | Level 3 | Other assets
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Included in Earnings	1
Purchases	7
Ending Balance	$ 8