Noninterest Revenue and Noninterest Expense - Card Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Disaggregation of Revenue [Line Items]
Total card income	$ 1,140	$ 1,345	$ 3,700	$ 3,895
Interchange and merchant processing income
Disaggregation of Revenue [Line Items]
Total card income	9,218	8,543	26,775	24,894
Rewards costs and partner payments
Disaggregation of Revenue [Line Items]
Total card income	(7,614)	(6,833)	(21,749)	(19,793)
All other
Disaggregation of Revenue [Line Items]
Total card income	$ (464)	$ (365)	$ (1,326)	$ (1,206)
Deferred revenues, recognition period	12 months		12 months