Asset Quality - Consumer Credit Exposure (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 106,600	$ 101,854
Accrued interest	193	198
Consumer Loans
Financing Receivable, Credit Quality Indicator [Line Items]
Current	2,979	13,637
One year prior	13,422	5,890
Two years prior	5,513	2,095
Three years prior	1,872	432
Four years prior	380	384
Prior	2,954	2,812
Revolving Loans Amortized Cost Basis	4,977	5,156
Revolving Loans Converted to Term Loans Amortized Cost Basis	583	612
Total	32,680	31,018
Accrued interest	75	85
Consumer Loans | Real estate — residential mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Current	1,850	9,636
One year prior	9,609	3,274
Two years prior	3,117	966
Three years prior	864	140
Four years prior	123	163
Prior	1,617	1,576
Revolving Loans Amortized Cost Basis	1	1
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	17,181	15,756
Consumer Loans | Real estate — residential mortgage | FICO Score, 750 and above
Financing Receivable, Credit Quality Indicator [Line Items]
Current	1,351	7,906
One year prior	8,320	2,909
Two years prior	2,802	777
Three years prior	705	84
Four years prior	74	126
Prior	1,135	1,096
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	14,387	12,898
Consumer Loans | Real estate — residential mortgage | FICO Score, 660 to 749
Financing Receivable, Credit Quality Indicator [Line Items]
Current	437	1,686
One year prior	1,235	351
Two years prior	299	169
Three years prior	140	39
Four years prior	32	25
Prior	302	308
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	2,445	2,578
Consumer Loans | Real estate — residential mortgage | FICO Score, Less than 660
Financing Receivable, Credit Quality Indicator [Line Items]
Current	12	26
One year prior	35	14
Two years prior	16	19
Three years prior	18	16
Four years prior	16	9
Prior	149	142
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	246	226
Consumer Loans | Real estate — residential mortgage | FICO Score, No Score
Financing Receivable, Credit Quality Indicator [Line Items]
Current	50	18
One year prior	19	0
Two years prior	0	1
Three years prior	1	1
Four years prior	1	3
Prior	31	30
Revolving Loans Amortized Cost Basis	1	1
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	103	54
Consumer Loans | Home equity loans
Financing Receivable, Credit Quality Indicator [Line Items]
Current	139	1,472
One year prior	1,458	1,119
Two years prior	1,064	382
Three years prior	350	153
Four years prior	138	181
Prior	1,054	964
Revolving Loans Amortized Cost Basis	3,472	3,584
Revolving Loans Converted to Term Loans Amortized Cost Basis	583	612
Total	8,258	8,467
Consumer Loans | Home equity loans | FICO Score, 750 and above
Financing Receivable, Credit Quality Indicator [Line Items]
Current	96	1,051
One year prior	1,073	830
Two years prior	797	251
Three years prior	233	96
Four years prior	87	128
Prior	731	666
Revolving Loans Amortized Cost Basis	2,209	2,244
Revolving Loans Converted to Term Loans Amortized Cost Basis	404	423
Total	5,630	5,689
Consumer Loans | Home equity loans | FICO Score, 660 to 749
Financing Receivable, Credit Quality Indicator [Line Items]
Current	40	394
One year prior	356	263
Two years prior	239	111
Three years prior	97	44
Four years prior	39	40
Prior	221	204
Revolving Loans Amortized Cost Basis	940	1,004
Revolving Loans Converted to Term Loans Amortized Cost Basis	135	143
Total	2,067	2,203
Consumer Loans | Home equity loans | FICO Score, Less than 660
Financing Receivable, Credit Quality Indicator [Line Items]
Current	3	27
One year prior	29	24
Two years prior	26	20
Three years prior	20	13
Four years prior	12	13
Prior	100	92
Revolving Loans Amortized Cost Basis	320	333
Revolving Loans Converted to Term Loans Amortized Cost Basis	44	46
Total	554	568
Consumer Loans | Home equity loans | FICO Score, No Score
Financing Receivable, Credit Quality Indicator [Line Items]
Current	0	0
One year prior	0	2
Two years prior	2	0
Three years prior	0	0
Four years prior	0	0
Prior	2	2
Revolving Loans Amortized Cost Basis	3	3
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	7	7
Consumer Loans | Consumer direct loans
Financing Receivable, Credit Quality Indicator [Line Items]
Current	990	2,524
One year prior	2,352	1,497
Two years prior	1,332	747
Three years prior	658	139
Four years prior	119	40
Prior	224	207
Revolving Loans Amortized Cost Basis	574	599
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	6,249	5,753
Consumer Loans | Consumer direct loans | FICO Score, 750 and above
Financing Receivable, Credit Quality Indicator [Line Items]
Current	741	1,799
One year prior	1,706	1,129
Two years prior	1,004	517
Three years prior	456	65
Four years prior	57	17
Prior	131	129
Revolving Loans Amortized Cost Basis	105	109
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	4,200	3,765
Consumer Loans | Consumer direct loans | FICO Score, 660 to 749
Financing Receivable, Credit Quality Indicator [Line Items]
Current	220	612
One year prior	536	295
Two years prior	262	174
Three years prior	151	46
Four years prior	39	10
Prior	50	45
Revolving Loans Amortized Cost Basis	203	212
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	1,461	1,394
Consumer Loans | Consumer direct loans | FICO Score, Less than 660
Financing Receivable, Credit Quality Indicator [Line Items]
Current	7	45
One year prior	53	33
Two years prior	32	27
Three years prior	25	11
Four years prior	9	3
Prior	13	12
Revolving Loans Amortized Cost Basis	55	60
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	194	191
Consumer Loans | Consumer direct loans | FICO Score, No Score
Financing Receivable, Credit Quality Indicator [Line Items]
Current	22	68
One year prior	57	40
Two years prior	34	29
Three years prior	26	17
Four years prior	14	10
Prior	30	21
Revolving Loans Amortized Cost Basis	211	218
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	394	403
Consumer Loans | Commercial credit card
Financing Receivable, Credit Quality Indicator [Line Items]
Current	0	0
One year prior	0	0
Two years prior	0	0
Three years prior	0	0
Four years prior	0	0
Prior	0	0
Revolving Loans Amortized Cost Basis	930	972
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	930	972
Consumer Loans | Commercial credit card | FICO Score, 750 and above
Financing Receivable, Credit Quality Indicator [Line Items]
Current	0	0
One year prior	0	0
Two years prior	0	0
Three years prior	0	0
Four years prior	0	0
Prior	0	0
Revolving Loans Amortized Cost Basis	467	500
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	467	500
Consumer Loans | Commercial credit card | FICO Score, 660 to 749
Financing Receivable, Credit Quality Indicator [Line Items]
Current	0	0
One year prior	0	0
Two years prior	0	0
Three years prior	0	0
Four years prior	0	0
Prior	0	0
Revolving Loans Amortized Cost Basis	376	387
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	376	387
Consumer Loans | Commercial credit card | FICO Score, Less than 660
Financing Receivable, Credit Quality Indicator [Line Items]
Current	0	0
One year prior	0	0
Two years prior	0	0
Three years prior	0	0
Four years prior	0	0
Prior	0	0
Revolving Loans Amortized Cost Basis	86	84
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	86	84
Consumer Loans | Commercial credit card | FICO Score, No Score
Financing Receivable, Credit Quality Indicator [Line Items]
Current	0	0
One year prior	0	0
Two years prior	0	0
Three years prior	0	0
Four years prior	0	0
Prior	0	0
Revolving Loans Amortized Cost Basis	1	1
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	1	1
Consumer Loans | Consumer indirect loans
Financing Receivable, Credit Quality Indicator [Line Items]
Current	0	5
One year prior	3	0
Two years prior	0	0
Three years prior	0	0
Four years prior	0	0
Prior	59	65
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	62	70
Consumer Loans | Consumer indirect loans | FICO Score, 750 and above
Financing Receivable, Credit Quality Indicator [Line Items]
Current	0	5
One year prior	3	0
Two years prior	0	0
Three years prior	0	0
Four years prior	0	0
Prior	28	30
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	31	35
Consumer Loans | Consumer indirect loans | FICO Score, 660 to 749
Financing Receivable, Credit Quality Indicator [Line Items]
Current	0	0
One year prior	0	0
Two years prior	0	0
Three years prior	0	0
Four years prior	0	0
Prior	21	26
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	21	26
Consumer Loans | Consumer indirect loans | FICO Score, Less than 660
Financing Receivable, Credit Quality Indicator [Line Items]
Current	0	0
One year prior	0	0
Two years prior	0	0
Three years prior	0	0
Four years prior	0	0
Prior	10	9
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	10	9
Consumer Loans | Consumer indirect loans | FICO Score, No Score
Financing Receivable, Credit Quality Indicator [Line Items]
Current	0	0
One year prior	0	0
Two years prior	0	0
Three years prior	0	0
Four years prior	0	0
Prior	0	0
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	$ 0	$ 0