MSR (Activity Related to Mortgage Banking Net Revenue) (Parenthetical) (Detail) - USD ($) $ in Millions		3 Months Ended			9 Months Ended
		Sep. 30, 2016	Sep. 30, 2015	Mar. 31, 2015	Sep. 30, 2016	Sep. 30, 2015	[2]
Mortgage Loans On Real Estate
Residential mortgage loan sales	[1]	$ 1,846	$ 1,421		$ 4,591	$ 3,798
Residential mortgage loans | Troubled Debt Restructuring
Mortgage Loans On Real Estate
Residential mortgage loan sales				$ 568

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

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