Goodwill and Intangible Assets - Components (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Schedule of Intangible Assets by Major Class [Line Items]
Goodwill, Gross	$ 14,480	$ 13,978
Goodwill	14,480	13,978	$ 13,978
Intangible Assets, Gross (Excluding Goodwill)	4,305	4,195
Accumulated Amortization	(3,264)	(2,879)
Intangible Assets, Net (Excluding Goodwill)	1,041	1,316
Intangible Assets Gross Including Goodwill	18,785	18,173
Total goodwill and other intangible assets, Net Carrying Value	15,521	15,294
Commercial MSRs, Gross	212	171
Commercial MSR, Accumulated Amortization	(51)	(24)
Consumer MSRs	68	53
Total MSRs, Gross	280	224
Servicing Asset at Amortized Cost	161	147
Total MSRs, Net	229	200
Servicing Asset at Amortized Cost, Amortization	$ 27	$ 21
Finite-Lived Intangible Assets, Remaining Amortization Period	5 years 10 months 24 days	6 years 1 month
PCCR intangibles
Schedule of Intangible Assets by Major Class [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	$ 2,156	$ 2,124
Accumulated Amortization	(1,467)	(1,152)
Intangible Assets, Net (Excluding Goodwill)	$ 689	$ 972
Finite-Lived Intangible Assets, Remaining Amortization Period	5 years 1 month 6 days	6 years
Core deposit intangibles
Schedule of Intangible Assets by Major Class [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	$ 1,771	$ 1,771
Accumulated Amortization	(1,662)	(1,569)
Intangible Assets, Net (Excluding Goodwill)	$ 109	$ 202
Finite-Lived Intangible Assets, Remaining Amortization Period	2 years 10 months 24 days	3 years 9 months 18 days
Other Intangible Assets [Member]
Schedule of Intangible Assets by Major Class [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	$ 378	$ 300
Accumulated Amortization	(135)	(158)
Intangible Assets, Net (Excluding Goodwill)	$ 243	$ 142
Finite-Lived Intangible Assets, Remaining Amortization Period	9 years 7 months 6 days	9 years 7 months 6 days