Goodwill and Intangible Assets - Components (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Dec. 31, 2014
Schedule of Intangible Assets by Major Class [Line Items]
Goodwill	$ 13,983		$ 13,983		$ 13,978
Goodwill, Gross	13,983		13,983		13,978
Total Intangible Assets, Gross (Excluding Goodwill)	4,166		4,166		4,195
Accumulated Amortization	(3,161)		(3,161)		(2,879)
Total Intangible assets, Net (Excluding Goodwill)	1,005		1,005		1,316
Total goodwill and other intangible assets, Net Carrying Value	14,988		14,988		15,294
Intangible Assets Gross Including Goodwill	18,149		18,149		18,173
Consumer MSRs	63		63		53
Commercial MSRs, Gross	204		204		171
Commercial MSR, Accumulated Amortization	(44)		(44)		(24)
Commercial MSRs, Net	160		160		147
Total MSRs, Gross	267		267		224
Total MSRs, Net	223		223		200
Indefinite lived assets	4		4		4
Amortization of Intangibles	106	$ 130	327	$ 409
PCCR intangibles
Schedule of Intangible Assets by Major Class [Line Items]
Total Intangible Assets, Gross (Excluding Goodwill)	2,156		2,156		2,124
Accumulated Amortization	(1,393)		(1,393)		(1,152)
Net Carrying Amount	763		763		972
Amortization of Intangibles	78	90	242	282
Core deposit intangibles
Schedule of Intangible Assets by Major Class [Line Items]
Total Intangible Assets, Gross (Excluding Goodwill)	1,771		1,771		1,771
Accumulated Amortization	(1,642)		(1,642)		(1,569)
Net Carrying Amount	129		129		202
Amortization of Intangibles	22	$ 31	73	$ 100
Other Intangible Assets [Member]
Schedule of Intangible Assets by Major Class [Line Items]
Total Intangible Assets, Gross (Excluding Goodwill)	239		239		300
Accumulated Amortization	(126)		(126)		(158)
Total Intangible assets, Net (Excluding Goodwill)	$ 113		$ 113		$ 142