Allowance for Credit Losses and Reserve for Unfunded Lending Commitments - Charge-Offs (Details) $ in Millions	9 Months Ended
Sep. 30, 2023 USD ($)
Financing Receivable, Credit Quality Indicator [Line Items]
2023	$ 54
2022	589
2021	571
2020	268
2019	275
Prior	294
Total Term Loans	2,051
Revolving Loans	5,479
Revolving Loans Converted to Term	66
Total	7,596
Credit Card:
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans	5,415
Revolving Loans Converted to Term	66
Total	5,481
Credit Card: \| Domestic Card
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans	5,100
Revolving Loans Converted to Term	56
Total	5,156
Credit Card: \| International card businesses
Financing Receivable, Credit Quality Indicator [Line Items]
Revolving Loans	315
Revolving Loans Converted to Term	10
Total	325
Consumer Banking:
Financing Receivable, Credit Quality Indicator [Line Items]
2023	52
2022	551
2021	524
2020	246
2019	141
Prior	90
Total Term Loans	1,604
Revolving Loans	49
Revolving Loans Converted to Term	0
Total	1,653
Consumer Banking: \| Auto
Financing Receivable, Credit Quality Indicator [Line Items]
2023	52
2022	551
2021	523
2020	246
2019	141
Prior	89
Total Term Loans	1,602
Revolving Loans	0
Revolving Loans Converted to Term	0
Total	1,602
Consumer Banking: \| Retail banking
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0
2022	0
2021	1
2020	0
2019	0
Prior	1
Total Term Loans	2
Revolving Loans	49
Revolving Loans Converted to Term	0
Total	51
Commercial Portfolio
Financing Receivable, Credit Quality Indicator [Line Items]
2023	2
2022	38
2021	47
2020	22
2019	134
Prior	204
Total Term Loans	447
Revolving Loans	15
Revolving Loans Converted to Term	0
Total	462
Commercial Portfolio \| Commercial and multifamily real estate
Financing Receivable, Credit Quality Indicator [Line Items]
2023	0
2022	29
2021	47
2020	22
2019	105
Prior	201
Total Term Loans	404
Revolving Loans	0
Revolving Loans Converted to Term	0
Total	404
Commercial Portfolio \| Commercial and industrial
Financing Receivable, Credit Quality Indicator [Line Items]
2023	2
2022	9
2021	0
2020	0
2019	29
Prior	3
Total Term Loans	43
Revolving Loans	15
Revolving Loans Converted to Term	0
Total	$ 58

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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

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-Topic 326
-SubTopic 20
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