Noninterest Revenue and Noninterest Expense - Card Income (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2024	Sep. 30, 2023	Sep. 30, 2024	Sep. 30, 2023
Disaggregation of Revenue [Line Items]
Total card income	$ 1,345	$ 1,209	$ 3,895	$ 3,537
Interchange and merchant processing income
Disaggregation of Revenue [Line Items]
Total card income	8,543	7,914	24,894	22,938
Rewards costs and partner payments
Disaggregation of Revenue [Line Items]
Total card income	(6,833)	(6,283)	(19,793)	(18,184)
Other card income
Disaggregation of Revenue [Line Items]
Total card income	$ (365)	$ (422)	$ (1,206)	$ (1,217)
Deferred revenues, recognition period	12 months		12 months