Goodwill and Intangible Assets - Goodwill Business Segments (Details) $ in Millions	6 Months Ended
	Jun. 30, 2021 USD ($)
Goodwill [Roll Forward]
Goodwill, beginning balance	$ 14,653
Other adjustments	1
Goodwill, ending balance	14,654
Credit Card
Goodwill [Roll Forward]
Goodwill, beginning balance	5,088
Other adjustments	1
Goodwill, ending balance	5,089
Consumer Banking
Goodwill [Roll Forward]
Goodwill, beginning balance	4,645
Other adjustments	0
Goodwill, ending balance	4,645
Commercial Banking
Goodwill [Roll Forward]
Goodwill, beginning balance	4,920
Other adjustments	0
Goodwill, ending balance	$ 4,920