Goodwill and Other Intangible Assets - Changes in the Carrying Amounts of Other Intangible Assets (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Servicing Asset at Fair Value, Amount		$ 1,307	$ 1,206
Intangible Assets, Net (Excluding Goodwill)		1,325	1,219	$ 1,334
Amortization	[1]	(8)	(12)
Origination of Mortgage Servicing Rights (MSRs)		251	178
Servicing Assets at Fair Value, Purchased		109	130
Due to changes in inputs or assumptions	[2]	(32)	(234)
Servicing Asset at Fair Value, Other Changes in Fair Value	[3]	(210)	(167)
Servicing Asset at Fair Value, Disposals		(4)	(1)
Intangible Assets, Written off Related to Sale of Business Unit			(9)
Mortgage Servicing Rights, Fair Value [Member]
Servicing Asset at Fair Value, Amount		1,307	1,206	1,300
Amortization		0	0
Origination of Mortgage Servicing Rights (MSRs)		238	178
Servicing Assets at Fair Value, Purchased		109	130
Due to changes in inputs or assumptions	[2]	(32)	(234)
Servicing Asset at Fair Value, Other Changes in Fair Value	[3]	(210)	(167)
Servicing Asset at Fair Value, Disposals		(4)	(1)
Intangible Assets, Written off Related to Sale of Business Unit			0
Other Intangible Assets [Member]
Intangible Assets, Net (Excluding Goodwill)		18	13	$ 34
Amortization	[1]	(8)	(12)
Origination of Mortgage Servicing Rights (MSRs)		13	0
Servicing Assets at Fair Value, Purchased		0	0
Due to changes in inputs or assumptions		0	0
Servicing Asset at Fair Value, Other Changes in Fair Value		0	0
Servicing Asset at Fair Value, Disposals		$ 0	0
Intangible Assets, Written off Related to Sale of Business Unit			$ (9)

[1] Does not include expense associated with non-qualified community development investments. See Note 10, "Certain Transfers of Financial Assets and Variable Interest Entities," for additional information.

[2] Primarily reflects changes in option adjusted spreads and prepayment speed assumptions, due to changes in interest rates.

[3] Represents changes due to the collection of expected cash flows, net of accretion due to the passage of time.