MSR (Activity Related to Mortgage Banking Net Revenue) (Detail) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale
Residential mortgage loan sales	[1]	$ 1,518	$ 1,631	$ 3,147	$ 2,745
Origination fees and gains on loan sales		37	54	66	95
Gross Mortgage Servicing Fees		$ 49	$ 50	$ 97	$ 102

[1] Represents the unpaid principal balance at the time of the sale.