Noninterest Revenue and Noninterest Expense - Card Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2024	Jun. 30, 2023	Jun. 30, 2024	Jun. 30, 2023
Disaggregation of Revenue [Line Items]
Total card income	$ 1,332	$ 1,094	$ 2,550	$ 2,328
Interchange and merchant processing income
Disaggregation of Revenue [Line Items]
Total card income	8,520	7,885	16,351	15,024
Rewards costs and partner payments
Disaggregation of Revenue [Line Items]
Total card income	(6,789)	(6,392)	(12,960)	(11,901)
Other card income
Disaggregation of Revenue [Line Items]
Total card income	$ (399)	$ (399)	$ (841)	$ (795)
Deferred revenues, recognition period	12 months		12 months