Activity Related to Mortgage Banking Net Revenue (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015		Dec. 31, 2014	Dec. 31, 2013
Securitization or Asset-backed Financing Arrangement, Financial Asset for which Transfer is Accounted as Sale
Residential mortgage loan sales	[2]	$ 5,078	[1]	$ 5,467	$ 21,529
Origination fees and gains on loan sales		171		153	453
Gross mortgage servicing fees		$ 222		$ 246	$ 251

[1] Excludes $568 of HFS residential mortgage loans previously modified in a TDR that were sold during the first quarter of 2015.

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