Allowance for Credit Losses and Reserve for Unfunded Lending Commitments - Charge-Offs (Details) $ in Millions	3 Months Ended
Mar. 31, 2024 USD ($)
Financing Receivable, Credit Quality Indicator [Line Items]
2024	$ 4
2023	138
2022	218
2021	167
2020	76
Prior	78
Total Term Loans	681
Revolving Loans	2,559
Revolving Loans Converted to Term	33
Total	3,273
Credit Card:
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans	2,541
Revolving Loans Converted to Term	33
Total	2,574
Credit Card: \| Domestic Card
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans	2,422
Revolving Loans Converted to Term	30
Total	2,452
Credit Card: \| International card businesses
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans	119
Revolving Loans Converted to Term	3
Total	122
Consumer Banking:
Financing Receivable, Credit Quality Indicator [Line Items]
2024	4
2023	138
2022	218
2021	163
2020	68
Prior	51
Total Term Loans	642
Revolving Loans	18
Revolving Loans Converted to Term	0
Total	660
Consumer Banking: \| Auto
Financing Receivable, Credit Quality Indicator [Line Items]
2024	4
2023	138
2022	218
2021	163
2020	68
Prior	51
Total Term Loans	642
Revolving Loans	0
Revolving Loans Converted to Term	0
Total	642
Consumer Banking: \| Retail banking
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0
2023	0
2022	0
2021	0
2020	0
Prior	0
Total Term Loans	0
Revolving Loans	18
Revolving Loans Converted to Term	0
Total	18
Commercial Banking:
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0
2023	0
2022	0
2021	4
2020	8
Prior	27
Total Term Loans	39
Revolving Loans	0
Revolving Loans Converted to Term	0
Total	39
Commercial Banking: \| Commercial and multifamily real estate
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0
2023	0
2022	0
2021	0
2020	0
Prior	27
Total Term Loans	27
Revolving Loans	0
Revolving Loans Converted to Term	0
Total	27
Commercial Banking: \| Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
2024	0
2023	0
2022	0
2021	4
2020	8
Prior	0
Total Term Loans	12
Revolving Loans	0
Revolving Loans Converted to Term	0
Total	$ 12

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Amount, excluding accrued interest, of decrease in allowance for credit loss on financing receivable from writeoff. Excludes net investment in lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 326
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
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Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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