Noninterest Revenue and Noninterest Expense - Card Income (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Disaggregation of Revenue [Line Items]
Total card income	$ 1,190	$ 1,216
Interchange and merchant processing income
Disaggregation of Revenue [Line Items]
Total card income	9,115	8,398
Rewards costs and partner payments
Disaggregation of Revenue [Line Items]
Total card income	(7,483)	(6,785)
All other
Disaggregation of Revenue [Line Items]
Total card income	$ (442)	$ (397)
Deferred revenues, recognition period	12 months	12 months