Asset Quality - Schedule of Consumer Credit Exposure (Details) - USD ($) $ in Millions	6 Months Ended	12 Months Ended
	Jun. 30, 2024	Dec. 31, 2023
Financing Receivable, Credit Quality Indicator [Line Items]
Total	$ 107,078	$ 112,606
Accrued interest	502	522
Total consumer loans
Financing Receivable, Credit Quality Indicator [Line Items]
Current	210	1,295
Writeoff, current period	1	0
One year prior	1,248	8,602
Writeoff, one year period	3	12
Two years prior	8,455	12,343
Writeoff, two year period	8	10
Three years prior	10,940	4,151
Writeoff, three year period	6	6
Four years prior	4,167	1,277
Writeoff, four year period	4	5
Prior	3,617	2,131
Writeoff, prior	5	6
Revolving Loans Amortized Cost Basis	4,505	4,747
Writeoff, Revolving Loans Amortized Cost Basis	32	51
Revolving Loans Converted to Term Loans Amortized Cost Basis	411	469
Revolving Loans Converted to Term Loans Amortized Cost Basis, writeoff	0	1
Total	33,553	35,015
Writeoff, total	59	91
Accrued interest	137	139
Total consumer loans | Real estate — residential mortgage
Financing Receivable, Credit Quality Indicator [Line Items]
Current	88	877
Writeoff, current period	1	0
One year prior	850	6,790
Writeoff, one year period	0	0
Two years prior	6,608	8,622
Writeoff, two year period	0	0
Three years prior	8,195	2,663
Writeoff, three year period	0	0
Four years prior	2,567	693
Writeoff, four year period	0	0
Prior	2,071	1,311
Writeoff, prior	1	1
Revolving Loans Amortized Cost Basis	1	2
Writeoff, Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis, writeoff	0	0
Total	20,380	20,958
Writeoff, total	2	1
Total consumer loans | Real estate — residential mortgage | 750 and above
Financing Receivable, Credit Quality Indicator [Line Items]
Current	64	680
One year prior	707	5,992
Two years prior	5,889	7,785
Three years prior	7,411	2,392
Four years prior	2,331	586
Prior	1,613	923
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	18,015	18,358
Total consumer loans | Real estate — residential mortgage | 660 to 749
Financing Receivable, Credit Quality Indicator [Line Items]
Current	23	180
One year prior	123	739
Two years prior	647	780
Three years prior	727	248
Four years prior	214	90
Prior	299	240
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	2,033	2,277
Total consumer loans | Real estate — residential mortgage | Less than 660
Financing Receivable, Credit Quality Indicator [Line Items]
Current	1	15
One year prior	18	58
Two years prior	71	56
Three years prior	56	22
Four years prior	21	17
Prior	143	130
Revolving Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	310	298
Total consumer loans | Real estate — residential mortgage | No Score
Financing Receivable, Credit Quality Indicator [Line Items]
Current	0	2
One year prior	2	1
Two years prior	1	1
Three years prior	1	1
Four years prior	1	0
Prior	16	18
Revolving Loans Amortized Cost Basis	1	2
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	22	25
Total consumer loans | Home equity loans
Financing Receivable, Credit Quality Indicator [Line Items]
Current	25	29
Writeoff, current period	0
One year prior	60	163
Writeoff, one year period	0
Two years prior	221	1,842
Writeoff, two year period	0
Three years prior	1,063	614
Writeoff, three year period	0
Four years prior	820	197
Writeoff, four year period	0
Prior	1,089	620
Writeoff, prior	1
Revolving Loans Amortized Cost Basis	3,040	3,205
Writeoff, Revolving Loans Amortized Cost Basis	0
Revolving Loans Converted to Term Loans Amortized Cost Basis	411	469
Revolving Loans Converted to Term Loans Amortized Cost Basis, writeoff	0
Total	6,729	7,139
Writeoff, total	1
Total consumer loans | Home equity loans | 750 and above
Financing Receivable, Credit Quality Indicator [Line Items]
Current	16	0
One year prior	35	85
Two years prior	150	1,575
Three years prior	819	435
Four years prior	656	114
Prior	785	378
Revolving Loans Amortized Cost Basis	1,955	2,034
Revolving Loans Converted to Term Loans Amortized Cost Basis	290	331
Total	4,706	4,952
Total consumer loans | Home equity loans | 660 to 749
Financing Receivable, Credit Quality Indicator [Line Items]
Current	8	24
One year prior	21	65
Two years prior	57	229
Three years prior	206	152
Four years prior	136	66
Prior	214	164
Revolving Loans Amortized Cost Basis	811	886
Revolving Loans Converted to Term Loans Amortized Cost Basis	95	107
Total	1,548	1,693
Total consumer loans | Home equity loans | Less than 660
Financing Receivable, Credit Quality Indicator [Line Items]
Current	1	3
One year prior	4	13
Two years prior	14	38
Three years prior	38	27
Four years prior	28	17
Prior	89	77
Revolving Loans Amortized Cost Basis	270	281
Revolving Loans Converted to Term Loans Amortized Cost Basis	26	31
Total	470	487
Total consumer loans | Home equity loans | No Score
Financing Receivable, Credit Quality Indicator [Line Items]
Current	0	2
One year prior	0	0
Two years prior	0	0
Three years prior	0	0
Four years prior	0	0
Prior	1	1
Revolving Loans Amortized Cost Basis	4	4
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	5	7
Total consumer loans | Home equity loans
Financing Receivable, Credit Quality Indicator [Line Items]
Writeoff, current period		(1)
Writeoff, one year period		0
Writeoff, two year period		0
Writeoff, three year period		0
Writeoff, four year period		0
Writeoff, prior		2
Writeoff, Revolving Loans Amortized Cost Basis		0
Revolving Loans Converted to Term Loans Amortized Cost Basis, writeoff		1
Writeoff, total		2
Total consumer loans | Other consumer loans
Financing Receivable, Credit Quality Indicator [Line Items]
Current	97	389
Writeoff, current period	0	1
One year prior	338	1,649
Writeoff, one year period	3	12
Two years prior	1,626	1,879
Writeoff, two year period	8	10
Three years prior	1,682	874
Writeoff, three year period	6	6
Four years prior	780	387
Writeoff, four year period	4	5
Prior	457	200
Writeoff, prior	3	3
Revolving Loans Amortized Cost Basis	534	538
Writeoff, Revolving Loans Amortized Cost Basis	8	14
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis, writeoff	0	0
Total	5,514	5,916
Writeoff, total	32	51
Total consumer loans | Other consumer loans | 750 and above
Financing Receivable, Credit Quality Indicator [Line Items]
Current	50	185
One year prior	168	1,187
Two years prior	1,233	1,455
Three years prior	1,304	660
Four years prior	600	277
Prior	290	112
Revolving Loans Amortized Cost Basis	89	97
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	3,734	3,973
Total consumer loans | Other consumer loans | 660 to 749
Financing Receivable, Credit Quality Indicator [Line Items]
Current	29	150
One year prior	125	365
Two years prior	309	342
Three years prior	302	171
Four years prior	141	83
Prior	119	60
Revolving Loans Amortized Cost Basis	187	199
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	1,212	1,370
Total consumer loans | Other consumer loans | Less than 660
Financing Receivable, Credit Quality Indicator [Line Items]
Current	3	24
One year prior	25	64
Two years prior	62	65
Three years prior	60	32
Four years prior	31	17
Prior	31	16
Revolving Loans Amortized Cost Basis	56	57
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	268	275
Total consumer loans | Other consumer loans | No Score
Financing Receivable, Credit Quality Indicator [Line Items]
Current	15	30
One year prior	20	33
Two years prior	22	17
Three years prior	16	11
Four years prior	8	10
Prior	17	12
Revolving Loans Amortized Cost Basis	202	185
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	300	298
Total consumer loans | Credit cards
Financing Receivable, Credit Quality Indicator [Line Items]
Current	0	0
Writeoff, current period	0	0
One year prior	0	0
Writeoff, one year period	0	0
Two years prior	0	0
Writeoff, two year period	0	0
Three years prior	0	0
Writeoff, three year period	0	0
Four years prior	0	0
Writeoff, four year period	0	0
Prior	0	0
Writeoff, prior	0	0
Revolving Loans Amortized Cost Basis	930	1,002
Writeoff, Revolving Loans Amortized Cost Basis	24	37
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Revolving Loans Converted to Term Loans Amortized Cost Basis, writeoff	0	0
Total	930	1,002
Writeoff, total	24	37
Total consumer loans | Credit cards | 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	450	489
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	450	489
Total consumer loans | Credit cards | 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	372	400
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	372	400
Total consumer loans | Credit cards | 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	107	112
Revolving Loans Converted to Term Loans Amortized Cost Basis	0	0
Total	107	112
Total consumer loans | Credit cards | 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