Loans and Allowance for Credit Losses - Amortized Cost Basis (Details) - USD ($) $ in Millions	Mar. 31, 2025	Dec. 31, 2024
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	$ 5,435	$ 8,718
Fiscal year before current fiscal year	7,110	2,627
Two years before current fiscal year	2,291	1,985
Three years before current fiscal year	1,323	3,319
Four years before current fiscal year	2,613	333
Prior	2,127	1,897
Revolving Loans	23,766	24,307
Total	44,665	43,186
Accrued interest receivable	340	327
Unsettled and was held-for-sale	20	14
Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Total	38,851	37,800
Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Total	5,114	4,687
Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total	250	249
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total	223	259
Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total	227	191
Commercial and Financial
Financing Receivable, Credit Quality Indicator [Line Items]
Total	41,969	40,344
Commercial and Financial | Domestic
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	2,230	3,827
Fiscal year before current fiscal year	2,573	406
Two years before current fiscal year	355	255
Three years before current fiscal year	184	488
Four years before current fiscal year	346	59
Prior	319	352
Revolving Loans	17,568	18,180
Total	23,575	23,567
Commercial and Financial | Non-U.S.
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	3,205	4,850
Fiscal year before current fiscal year	4,496	2,005
Two years before current fiscal year	1,720	1,222
Three years before current fiscal year	775	2,484
Four years before current fiscal year	1,919	46
Prior	81	43
Revolving Loans	6,198	6,127
Total	18,394	16,777
Commercial and Financial | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Total	37,104	35,831
Commercial and Financial | Investment grade | Domestic
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	1,812	1,946
Fiscal year before current fiscal year	875	223
Two years before current fiscal year	222	89
Three years before current fiscal year	39	47
Four years before current fiscal year	47	6
Prior	203	197
Revolving Loans	17,163	18,044
Total	20,361	20,552
Commercial and Financial | Investment grade | Non-U.S.
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	2,786	4,243
Fiscal year before current fiscal year	3,836	1,796
Two years before current fiscal year	1,634	1,152
Three years before current fiscal year	724	2,187
Four years before current fiscal year	1,696	0
Prior	0	0
Revolving Loans	6,067	5,901
Total	16,743	15,279
Commercial and Financial | Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Total	4,651	4,278
Commercial and Financial | Speculative | Domestic
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	418	1,834
Fiscal year before current fiscal year	1,651	173
Two years before current fiscal year	133	154
Three years before current fiscal year	133	387
Four years before current fiscal year	284	53
Prior	116	155
Revolving Loans	405	136
Total	3,140	2,892
Commercial and Financial | Speculative | Non-U.S.
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	376	607
Fiscal year before current fiscal year	660	174
Two years before current fiscal year	50	44
Three years before current fiscal year	51	246
Four years before current fiscal year	186	46
Prior	57	43
Revolving Loans	131	226
Total	1,511	1,386
Commercial and Financial | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total	165	187
Commercial and Financial | Special mention | Domestic
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	47
Fiscal year before current fiscal year	47	10
Two years before current fiscal year	0	0
Three years before current fiscal year	0	54
Four years before current fiscal year	15	0
Prior	0	0
Revolving Loans	0	0
Total	62	111
Commercial and Financial | Special mention | Non-U.S.
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	43	0
Fiscal year before current fiscal year	0	35
Two years before current fiscal year	36	26
Three years before current fiscal year	0	15
Four years before current fiscal year	0	0
Prior	24	0
Revolving Loans	0	0
Total	103	76
Commercial and Financial | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total	49	48
Commercial and Financial | Substandard | Domestic
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	12
Three years before current fiscal year	12	0
Four years before current fiscal year	0	0
Prior	0	0
Revolving Loans	0	0
Total	12	12
Commercial and Financial | Substandard | Non-U.S.
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	0
Three years before current fiscal year	0	36
Four years before current fiscal year	37	0
Prior	0	0
Revolving Loans	0	0
Total	37	36
Commercial and Financial | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total	0	0
Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Total	2,696	2,842
Commercial real estate | Domestic
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	41
Fiscal year before current fiscal year	41	216
Two years before current fiscal year	216	508
Three years before current fiscal year	364	347
Four years before current fiscal year	348	228
Prior	1,727	1,502
Revolving Loans	0	0
Total	2,696	2,842
Commercial real estate | Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Total	1,747	1,969
Commercial real estate | Investment grade | Domestic
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	41
Fiscal year before current fiscal year	41	63
Two years before current fiscal year	63	488
Three years before current fiscal year	344	278
Four years before current fiscal year	317	128
Prior	982	971
Revolving Loans	0	0
Total	1,747	1,969
Commercial real estate | Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Total	463	409
Commercial real estate | Speculative | Domestic
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	153
Two years before current fiscal year	153	20
Three years before current fiscal year	20	69
Four years before current fiscal year	31	100
Prior	259	67
Revolving Loans	0	0
Total	463	409
Commercial real estate | Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Total	85	62
Commercial real estate | Special mention | Domestic
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Prior	85	62
Revolving Loans	0	0
Total	85	62
Commercial real estate | Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Total	174	211
Commercial real estate | Substandard | Domestic
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Prior	174	211
Revolving Loans	0	0
Total	174	211
Commercial real estate | Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Total	227	191
Commercial real estate | Doubtful | Domestic
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Prior	227	191
Revolving Loans	0	0
Total	$ 227	$ 191