MSR (Sales of Receivables and Servicing Rights - Additional Information) (Detail) - USD ($)		3 Months Ended			6 Months Ended
		Jun. 30, 2016	Jun. 30, 2015	Mar. 31, 2015	Jun. 30, 2016	Jun. 30, 2015		Dec. 31, 2015
Servicing Rights at Fair Value
Residential mortgage loan sales	[1]	$ 1,631,000,000	$ 1,377,000,000		$ 2,745,000,000	$ 2,378,000,000	[2]
Sevicing of residential mortgage loans for other investors		56,200,000,000			56,200,000,000			$ 59,000,000,000
Amortization		$ (35,000,000)	$ (40,000,000)		$ (61,000,000)	$ (74,000,000)
Residential Mortgage Loans | Troubled Debt Restructuring
Servicing Rights at Fair Value
Gain on sale of HFS loans				$ 37,000,000
Residential mortgage loan sales				$ 568,000,000

[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 .