Goodwill and Intangible Assets - Components (Detail) - USD ($) $ in Millions	Jun. 30, 2017	Dec. 31, 2016
Schedule of Intangible Assets by Major Class [Line Items]
Goodwill, Gross	$ 14,524	$ 14,519
Goodwill	14,524	14,519
Intangible Assets, Gross (Excluding Goodwill)	3,856	3,856
Accumulated Amortization	(3,314)	(3,191)
Intangible Assets, Net (Excluding Goodwill)	542	665
Intangible Assets Gross Including Goodwill	18,380	18,375
Total goodwill and other intangible assets, Net Carrying Value	15,066	15,184
Commercial MSRs, Gross	314	276
Commercial MSR, Accumulated Amortization	(102)	(82)
Consumer MSRs	85	80
Total MSRs, Gross	399	356
Servicing Asset at Amortized Cost	212	194
Total MSRs, Net	297	274
PCCR intangibles
Schedule of Intangible Assets by Major Class [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	2,151	2,151
Accumulated Amortization	(1,802)	(1,715)
Intangible Assets, Net (Excluding Goodwill)	349	436
Core deposit intangibles
Schedule of Intangible Assets by Major Class [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	1,391	1,391
Accumulated Amortization	(1,360)	(1,345)
Intangible Assets, Net (Excluding Goodwill)	31	46
Other Intangible Assets [Member]
Schedule of Intangible Assets by Major Class [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	314	314
Accumulated Amortization	(152)	(131)
Intangible Assets, Net (Excluding Goodwill)	$ 162	$ 183