Fair Value (Reconciliation of Recurring Fair Value Measurements) (Details) - Fair Value, Recurring - Level 3 - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	$ 6,546	$ 6,305	$ 5,882	$ 5,137
Included in Earnings	481	382	1,283	957
Included in other comprehensive income	(21)	(5)	(102)	17
Purchases	497	213	966	879
Sales	(311)	(733)	(425)	(876)
Issuances	28	46	101	122
Settlements	(207)	(314)	(676)	(903)
Transfers into Level 3	8	4	22	12
Transfers out of Level 3	(16)	(11)	(46)	(29)
Impact from BBVA Acquisition		17		588
Ending Balance	7,005	5,904	7,005	5,904
Unrealized gains/losses on assets held on Consolidated Balance Sheet	379	218	1,183	750
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	398	326	463	318
Included in Earnings	15	210	59	263
Purchases	32		32
Sales	4	3	10	6
Issuances	362	7	608	325
Settlements	(420)	(44)	(781)	(417)
Impact from BBVA Acquisition				7
Ending Balance	391	502	391	502
Unrealized gains/losses on liabilities held on Consolidated Balance Sheet	17	215	61	237
Fair Value Additional Information [Abstract]
Net gains (losses) included in earnings (realized and unrealized) relating to Level 3 assets and liabilities	466	172	1,224	694
Net unrealized gains (losses) relating to Level 3 assets and liabilities	362	3	1,122	513
Loans held for sale | Residential mortgage loans held for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	83	119	81	163
Included in Earnings	(4)	(1)	(6)	(1)
Purchases	46	5	91	43
Sales	(1)	(29)	(33)	(81)
Settlements	(2)	(6)	(11)	(34)
Transfers into Level 3	8	4	22	12
Transfers out of Level 3	(14)	(6)	(28)	(16)
Ending Balance	116	86	116	86
Unrealized gains/losses on assets held on Consolidated Balance Sheet	(4)	(1)	(6)	(1)
Loans held for sale | Commercial mortgage loans held for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	38	52	49	57
Included in Earnings		(1)	(4)	(1)
Sales				(6)
Settlements	(3)		(10)	1
Ending Balance	35	51	35	51
Unrealized gains/losses on assets held on Consolidated Balance Sheet			(4)	1
Loans held for sale | Other consumer loans held for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance		239
Sales		(256)		(256)
Impact from BBVA Acquisition		17		256
Securities available for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1,133	1,496	1,332	1,647
Included in Earnings	4	11	20	32
Included in other comprehensive income	(21)	(5)	(102)	17
Purchases		2	3	5
Sales		9		(9)
Settlements	(46)	(83)	(183)	(280)
Ending Balance	1,070	1,412	1,070	1,412
Securities available for sale | Residential mortgage-backed
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	925	1,237	1,097	1,365
Included in Earnings	4	10	19	30
Included in other comprehensive income	(18)	(2)	(84)	14
Settlements	(40)	(77)	(161)	(241)
Ending Balance	871	1,168	871	1,168
Securities available for sale | Commercial mortgage-backed
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	3	11	3	11
Included in other comprehensive income		(8)		(8)
Ending Balance	3	3	3	3
Securities available for sale | Asset-backed
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	138	175	163	199
Included in Earnings		1	1	2
Included in other comprehensive income	(5)	5	(18)	10
Settlements	(6)	(9)	(19)	(39)
Ending Balance	127	172	127	172
Securities available for sale | Other
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	67	73	69	72
Included in other comprehensive income	2			1
Purchases		2	3	5
Sales		9		(9)
Settlements		3	(3)
Ending Balance	69	69	69	69
Loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	804	979	884	647
Included in Earnings	(1)	12	20	32
Purchases	11	14	31	111
Sales	(2)	(6)	(10)	(12)
Settlements	(35)	(58)	(132)	(121)
Transfers out of Level 3	(2)	(5)	(18)	(13)
Impact from BBVA Acquisition				292
Ending Balance	775	936	775	936
Unrealized gains/losses on assets held on Consolidated Balance Sheet		12	20	32
Equity investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1,867	1,540	1,680	1,263
Included in Earnings	167	265	312	489
Purchases	69	158	185	290
Sales	(308)	(433)	(382)	(512)
Ending Balance	1,795	1,530	1,795	1,530
Unrealized gains/losses on assets held on Consolidated Balance Sheet	65	95	211	294
Mortgage Servicing Rights | Residential mortgage loans held for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	1,620	1,111	1,078	673
Included in Earnings	135	49	505	203
Purchases	363	28	620	400
Issuances	11	24	49	61
Settlements	(55)	(82)	(178)	(242)
Impact from BBVA Acquisition				35
Ending Balance	2,074	1,130	2,074	1,130
Unrealized gains/losses on assets held on Consolidated Balance Sheet	135	49	506	203
Mortgage Servicing Rights | Commercial mortgage loans held for sale
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	988	682	740	569
Included in Earnings	176	24	438	134
Purchases	7	5	32	26
Issuances	17	22	52	61
Settlements	(56)	(30)	(130)	(87)
Ending Balance	1,132	703	1,132	703
Unrealized gains/losses on assets held on Consolidated Balance Sheet	176	24	438	134
Financial derivatives
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	13	87	38	118
Included in Earnings	4	23	(2)	69
Purchases	1	1	4	4
Settlements	(10)	(55)	(32)	(140)
Impact from BBVA Acquisition				5
Ending Balance	8	56	8	56
Unrealized gains/losses on assets held on Consolidated Balance Sheet	7	39	18	87
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	213	200	285	273
Included in Earnings	(11)	165	12	155
Sales	4	3	10	6
Settlements	(86)	(37)	(187)	(110)
Impact from BBVA Acquisition				7
Ending Balance	120	331	120	331
Unrealized gains/losses on liabilities held on Consolidated Balance Sheet	(7)	171	22	156
Other borrowed funds
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	3	2	3	2
Issuances		3	4	4
Settlements	(1)	(1)	(5)	(2)
Ending Balance	2	4	2	4
Other liabilities
Fair Value, Liabilities Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Beginning Balance	182	124	175	43
Included in Earnings	26	45	47	108
Purchases	32		32
Issuances	362	4	604	321
Settlements	(333)	(6)	(589)	(305)
Ending Balance	269	167	269	167
Unrealized gains/losses on liabilities held on Consolidated Balance Sheet	$ 24	$ 44	$ 39	$ 81