Loans - By Portfolio Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Dec. 31, 2024
Loan balances by portfolio segment:
Retained	$ 1,369,785	$ 1,285,370	$ 1,369,785	$ 1,285,370	$ 1,299,590
Held-for-sale	10,775		10,775		7,048
Loans at fair value	54,686		54,686		41,350
Total	1,435,246		1,435,246		1,347,988
Accrued interest receivables	6,900		6,900		6,600
Accrued interest receivables written off	22	0	85	0
Consumer, excluding credit card
Loan balances by portfolio segment:
Retained	369,859	377,938	369,859	377,938	376,334
Held-for-sale	384		384		945
Loans at fair value	22,841		22,841		15,531
Total	393,084		393,084		392,810
Credit card
Loan balances by portfolio segment:
Retained	235,475		235,475		232,860
Held-for-sale	0		0		0
Loans at fair value	0		0		0
Total	235,475		235,475		232,860
Wholesale
Loan balances by portfolio segment:
Retained	764,451	$ 687,890	764,451	$ 687,890	690,396
Held-for-sale	10,391		10,391		6,103
Loans at fair value	31,845		31,845		25,819
Total	$ 806,687		$ 806,687		$ 722,318