Fair Value (Reconciliation ofLevel 3 Assets and Liabilities) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021
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	$ 5,882	$ 5,137
Included in Earnings	1,457	1,147
Included in Other comprehensive income (b)	(126)	8
Purchases	1,529	1,207
Sales	(816)	(1,143)
Issuances	119	174
Settlements	(896)	(1,218)
Transfers into Level 3	163	18
Transfers out of Level 3	(60)	(36)
Impact from BBVA Acquisition		588
Ending Balance	7,252	5,882
Unrealized gains (losses) on assets held on Consolidated Balance Sheet	1,250	847
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	463	318
Included in Earnings	126	296
Purchases	32
Sales	14	6
Issuances	883	326
Settlements	(1,097)	(490)
Impact from BBVA Acquisition		7
Ending Balance	421	463
Unrealized gains or (losses) on liabilities held on Consolidated Balance Sheet	128	269
Fair Value Additional Information [Abstract]
Net gains (losses) included in earnings (realized and unrealized) relating to Level 3 assets and liabilities	1,331	851
Net unrealized gains (losses) relating to Level 3 assets and liabilities	1,122	578
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	81	163
Included in Earnings	(5)	(1)
Purchases	226	47
Sales	(34)	(83)
Settlements	(13)	(41)
Transfers into Level 3	29	18
Transfers out of Level 3	(41)	(22)
Ending Balance	243	81
Unrealized gains (losses) on assets held on Consolidated Balance Sheet	(5)	(1)
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	49	57
Included in Earnings	(6)
Sales		(6)
Settlements	(10)	(2)
Ending Balance	33	49
Unrealized gains (losses) on assets held on Consolidated Balance Sheet	(6)	(1)
Fair Value, Measurements, Recurring | Level 3 | Loans Held For Sale | Other consumer loans held for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Sales		(256)
Impact from BBVA Acquisition		256
Fair Value, Measurements, Recurring | Level 3 | Securities available for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1,332	1,647
Included in Earnings	24	39
Included in Other comprehensive income (b)	(126)	8
Purchases	6	6
Settlements	(235)	(368)
Ending Balance	1,001	1,332
Fair Value, Measurements, Recurring | Level 3 | Securities available for sale | Residential mortgage-backed Securities
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1,097	1,365
Included in Earnings	22	37
Included in Other comprehensive income (b)	(108)	6
Settlements	(192)	(311)
Ending Balance	819	1,097
Fair Value, Measurements, Recurring | Level 3 | Securities available for sale | Commercial mortgage- backed non-agency
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	3	11
Included in Other comprehensive income (b)		(8)
Ending Balance	3	3
Fair Value, Measurements, Recurring | Level 3 | Securities available for sale | Asset-backed
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	163	199
Included in Earnings	2	2
Included in Other comprehensive income (b)	(18)	9
Settlements	(23)	(47)
Ending Balance	124	163
Fair Value, Measurements, Recurring | Level 3 | Securities available for sale | Other debt
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	69	72
Included in Other comprehensive income (b)		1
Purchases	6	6
Settlements	(20)	(10)
Ending Balance	55	69
Fair Value, Measurements, Recurring | Level 3 | Loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	884	647
Included in Earnings	23	45
Purchases	55	124
Sales	(10)	(15)
Settlements	(164)	(194)
Transfers out of Level 3	(19)	(14)
Impact from BBVA Acquisition		291
Ending Balance	769	884
Unrealized gains (losses) on assets held on Consolidated Balance Sheet	23	44
Fair Value, Measurements, Recurring | Level 3 | Equity investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1,680	1,263
Included in Earnings	445	627
Purchases	291	573
Sales	(772)	(783)
Transfers into Level 3	134
Ending Balance	1,778	1,680
Unrealized gains (losses) on assets held on Consolidated Balance Sheet	237	338
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	1,078	673
Included in Earnings	509	192
Purchases	897	411
Issuances	57	87
Settlements	(231)	(320)
Impact from BBVA Acquisition		35
Ending Balance	2,310	1,078
Unrealized gains (losses) on assets held on Consolidated Balance Sheet	509	192
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	740	569
Included in Earnings	473	162
Purchases	46	41
Issuances	62	87
Settlements	(208)	(119)
Ending Balance	1,113	740
Unrealized gains (losses) on assets held on Consolidated Balance Sheet	473	162
Fair Value, Measurements, Recurring | Level 3 | Financial derivatives
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	38	118
Included in Earnings	(6)	83
Purchases	8	5
Settlements	(35)	(174)
Impact from BBVA Acquisition		6
Ending Balance	5	38
Unrealized gains (losses) on assets held on Consolidated Balance Sheet	19	113
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	285	273
Included in Earnings	49	145
Sales	14	6
Settlements	(225)	(146)
Impact from BBVA Acquisition		7
Ending Balance	123	285
Unrealized gains or (losses) on liabilities held on Consolidated Balance Sheet	62	158
Fair Value, Measurements, Recurring | Level 3 | Other borrowed funds
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	3	2
Issuances	7	5
Settlements	(6)	(4)
Ending Balance	4	3
Fair Value, Measurements, Recurring | Level 3 | Other liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	175	43
Included in Earnings	77	151
Purchases	32
Issuances	876	321
Settlements	(866)	(340)
Ending Balance	294	175
Unrealized gains or (losses) on liabilities held on Consolidated Balance Sheet	$ 66	$ 111