Goodwill and Intangible Assets - Goodwill Attributable to Each Business Segments (Detail) $ in Millions	3 Months Ended
	Mar. 31, 2017 USD ($)
Goodwill [Roll Forward]
Goodwill, Beginning Balance	$ 14,519
Other adjustments	2
Goodwill, Ending Balance	14,521
Commercial Banking
Goodwill [Roll Forward]
Goodwill, Beginning Balance	4,901
Other adjustments	0
Goodwill, Ending Balance	4,901
Credit Card
Goodwill [Roll Forward]
Goodwill, Beginning Balance	5,018
Other adjustments	2
Goodwill, Ending Balance	5,020
Consumer Banking
Goodwill [Roll Forward]
Goodwill, Beginning Balance	4,600
Other adjustments	0
Goodwill, Ending Balance	$ 4,600