Goodwill and Intangible Assets - Components (Detail) - USD ($) $ in Millions	Sep. 30, 2019	Dec. 31, 2018
Schedule of Intangible Assets by Major Class [Line Items]
Goodwill, gross	$ 14,624	$ 14,544
Goodwill	14,624	14,544
Intangible Assets, Gross (Excluding Goodwill)	2,157	3,522
Accumulated Amortization	(1,976)	(3,268)
Intangible Assets, Net (Excluding Goodwill)	181	254
Intangible Assets Gross Including Goodwill	16,781	18,066
Total goodwill and other intangible assets, Net Carrying Value	14,805	14,798
Commercial MSRs, Gross	528	459
Commercial MSR, Accumulated Amortization	(237)	(185)
Servicing Asset at Amortized Cost	291	274
PCCR intangibles
Schedule of Intangible Assets by Major Class [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	1,932	2,102
Accumulated Amortization	(1,844)	(1,952)
Intangible Assets, Net (Excluding Goodwill)	88	150
Core deposit intangibles
Schedule of Intangible Assets by Major Class [Line Items]
Intangible Assets, Gross (Excluding Goodwill)		1,149
Accumulated Amortization		(1,148)
Intangible Assets, Net (Excluding Goodwill)		1
Other intangible assets
Schedule of Intangible Assets by Major Class [Line Items]
Intangible Assets, Gross (Excluding Goodwill)	225	271
Accumulated Amortization	(132)	(168)
Intangible Assets, Net (Excluding Goodwill)	$ 93	$ 103