Noninterest Revenue and Noninterest Expense - Card Income (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021
Disaggregation of Revenue [Line Items]
Total card income	$ 1,133	$ 1,647	$ 2,108	$ 2,997
Interchange and merchant processing income
Disaggregation of Revenue [Line Items]
Total card income	7,214	5,974	13,449	10,842
Rewards costs and partner payments
Disaggregation of Revenue [Line Items]
Total card income	(5,641)	(4,282)	(10,511)	(7,816)
Other card income
Disaggregation of Revenue [Line Items]
Total card income	$ (440)	$ (45)	$ (830)	$ (29)