Loans and Allowance for Credit Losses - Amortized Cost Basis (Details) - USD ($) $ in Millions	Sep. 30, 2023	Dec. 31, 2022
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	$ 5,307	$ 5,839
Fiscal year before current fiscal year	2,997	5,104
Two years before current fiscal year	4,984	512
Three years before current fiscal year	432	1,636
Four years before current fiscal year	1,308	1,092
Prior	1,438	668
Revolving Loans	18,963	17,294
Loans, gross, excluding loans classified as held-for-sale	35,429	32,145
Financing receivable, accrued interest, before allowance for credit loss	325	200
Financing receivable, held-for-sale	7	5
Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	30,595	27,176
Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	4,352	4,491
Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	367	379
Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	39	99
Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	76
Commercial and Financial
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	32,312	29,160
Commercial and Financial \| Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	28,160	24,667
Commercial and Financial \| Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	3,816	4,103
Commercial and Financial \| Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	268	291
Commercial and Financial \| Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	39	99
Commercial and Financial \| Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	29
Commercial and Financial \| Domestic
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	1,578	2,100
Fiscal year before current fiscal year	364	1,164
Two years before current fiscal year	1,132	245
Three years before current fiscal year	179	908
Four years before current fiscal year	663	286
Prior	191	167
Revolving Loans	14,277	13,388
Loans, gross, excluding loans classified as held-for-sale	18,384	18,258
Commercial and Financial \| Domestic \| Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	1,095	1,577
Fiscal year before current fiscal year	100	185
Two years before current fiscal year	204	72
Three years before current fiscal year	61	300
Four years before current fiscal year	272	0
Prior	6	9
Revolving Loans	13,930	12,843
Loans, gross, excluding loans classified as held-for-sale	15,668	14,986
Commercial and Financial \| Domestic \| Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	458	523
Fiscal year before current fiscal year	264	859
Two years before current fiscal year	749	168
Three years before current fiscal year	113	461
Four years before current fiscal year	334	236
Prior	185	151
Revolving Loans	347	545
Loans, gross, excluding loans classified as held-for-sale	2,450	2,943
Commercial and Financial \| Domestic \| Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	0	120
Two years before current fiscal year	155	0
Three years before current fiscal year	0	105
Four years before current fiscal year	57	19
Prior	0	0
Revolving Loans	0	0
Loans, gross, excluding loans classified as held-for-sale	212	244
Commercial and Financial \| Domestic \| Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	20	0
Fiscal year before current fiscal year	0	0
Two years before current fiscal year	0	5
Three years before current fiscal year	5	42
Four years before current fiscal year	0	31
Prior	0	7
Revolving Loans	0	0
Loans, gross, excluding loans classified as held-for-sale	25	85
Commercial and Financial \| Domestic \| Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	5
Fiscal year before current fiscal year	0
Two years before current fiscal year	24
Three years before current fiscal year	0
Four years before current fiscal year	0
Prior	0
Revolving Loans	0
Loans, gross, excluding loans classified as held-for-sale	29
Commercial and Financial \| Non-U.S.
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	3,514	3,220
Fiscal year before current fiscal year	2,113	3,328
Two years before current fiscal year	3,323	118
Three years before current fiscal year	103	186
Four years before current fiscal year	104	144
Prior	85	0
Revolving Loans	4,686	3,906
Loans, gross, excluding loans classified as held-for-sale	13,928	10,902
Commercial and Financial \| Non-U.S. \| Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	3,031	2,986
Fiscal year before current fiscal year	1,982	2,799
Two years before current fiscal year	2,793	0
Three years before current fiscal year	0	0
Four years before current fiscal year	0	0
Prior	0	0
Revolving Loans	4,686	3,897
Loans, gross, excluding loans classified as held-for-sale	12,492	9,682
Commercial and Financial \| Non-U.S. \| Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	483	234
Fiscal year before current fiscal year	131	529
Two years before current fiscal year	502	100
Three years before current fiscal year	75	181
Four years before current fiscal year	104	107
Prior	71	0
Revolving Loans	0	9
Loans, gross, excluding loans classified as held-for-sale	1,366	1,160
Commercial and Financial \| Non-U.S. \| Special mention
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	28	18
Three years before current fiscal year	28	5
Four years before current fiscal year	0	23
Prior	0	0
Revolving Loans	0	0
Loans, gross, excluding loans classified as held-for-sale	56	46
Commercial and Financial \| Non-U.S. \| Substandard
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	14
Prior	14	0
Revolving Loans	0	0
Loans, gross, excluding loans classified as held-for-sale	14	14
Commercial real estate
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	3,117	2,985
Commercial real estate \| Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	2,435	2,509
Commercial real estate \| Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	536	388
Commercial real estate \| Special mention
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	99	88
Commercial real estate \| Substandard
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	0	0
Commercial real estate \| Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Loans, gross, excluding loans classified as held-for-sale	47
Commercial real estate \| Domestic
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	215	519
Fiscal year before current fiscal year	520	612
Two years before current fiscal year	529	149
Three years before current fiscal year	150	542
Four years before current fiscal year	541	662
Prior	1,162	501
Revolving Loans	0	0
Loans, gross, excluding loans classified as held-for-sale	3,117	2,985
Commercial real estate \| Domestic \| Investment grade
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	215	519
Fiscal year before current fiscal year	500	612
Two years before current fiscal year	498	100
Three years before current fiscal year	100	330
Four years before current fiscal year	375	511
Prior	747	436
Revolving Loans	0	0
Loans, gross, excluding loans classified as held-for-sale	2,435	2,508
Commercial real estate \| Domestic \| Speculative
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0	0
Fiscal year before current fiscal year	20	0
Two years before current fiscal year	31	49
Three years before current fiscal year	50	163
Four years before current fiscal year	144	111
Prior	291	65
Revolving Loans	0	0
Loans, gross, excluding loans classified as held-for-sale	536	388
Commercial real estate \| Domestic \| Special mention
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	49
Four years before current fiscal year	22	40
Prior	77	0
Revolving Loans	0	0
Loans, gross, excluding loans classified as held-for-sale	99	$ 89
Commercial real estate \| Domestic \| Doubtful
Financing Receivable, Credit Quality Indicator [Line Items]
Current fiscal year	0
Fiscal year before current fiscal year	0
Two years before current fiscal year	0
Three years before current fiscal year	0
Four years before current fiscal year	0
Prior	47
Revolving Loans	0
Loans, gross, excluding loans classified as held-for-sale	$ 47

Financing Receivable, Excluding Accrued Interest, Before Allowance For Credit Loss, Excluding Held For Sale Receivables

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Amount, before allowance for credit loss, of accrued interest on financing receivable.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
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Amortized cost excluding accrued interest, of financing receivable originated more than five years prior to current fiscal year. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 326
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Amortized cost excluding accrued interest, of financing receivable that can be withdrawn, repaid, and redrawn.

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Amortized cost excluding accrued interest, of financing receivable originated four years prior to current fiscal year. Excludes net investment in lease.

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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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