Goodwill and Intangible Assets - Goodwill Attributable to Each Business Segments (Detail) $ in Millions	6 Months Ended
	Jun. 30, 2017 USD ($)
Goodwill [Roll Forward]
Goodwill, Beginning Balance	$ 14,519
Goodwill, Acquired During Period	0
Other adjustments	5
Goodwill, Ending Balance	14,524
Commercial Banking
Goodwill [Roll Forward]
Goodwill, Beginning Balance	4,901
Goodwill, Acquired During Period	0
Other adjustments	0
Goodwill, Ending Balance	4,901
Credit Card
Goodwill [Roll Forward]
Goodwill, Beginning Balance	5,018
Goodwill, Acquired During Period	0
Other adjustments	5
Goodwill, Ending Balance	5,023
Consumer Banking
Goodwill [Roll Forward]
Goodwill, Beginning Balance	4,600
Goodwill, Acquired During Period	0
Other adjustments	0
Goodwill, Ending Balance	$ 4,600