Goodwill and Other Intangible Assets - Changes in the Carrying Amounts of Other Intangible Assets (Detail) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Servicing Asset at Fair Value, Amount		$ 1,572	$ 1,307
Intangible Assets, Net (Excluding Goodwill)		1,657	1,325	$ 1,219
Amortization	[1]	(9)	(8)
Origination of Mortgage Servicing Rights (MSRs)		312	251
Intangible Assets Acquired	[2]	14
Servicing Assets at Fair Value, Purchased		200	109
Due to changes in inputs or assumptions	[3]	(13)	(32)
Servicing Asset at Fair Value, Other Changes in Fair Value	[4]	(232)	(210)
Servicing Asset at Fair Value, Disposals		(2)	(4)
Mortgage Servicing Rights, Fair Value [Member]
Servicing Asset at Fair Value, Amount		1,572	1,307	1,206
Amortization	[1]	0	0
Origination of Mortgage Servicing Rights (MSRs)		312	238
Servicing Assets at Fair Value, Purchased		200	109
Due to changes in inputs or assumptions	[3]	(13)	(32)
Servicing Asset at Fair Value, Other Changes in Fair Value	[4]	(232)	(210)
Servicing Asset at Fair Value, Disposals		(2)	(4)
Other Intangible Assets [Member]
Intangible Assets, Net (Excluding Goodwill)		85	18	$ 13
Amortization	[1]	(9)	(8)
Origination of Mortgage Servicing Rights (MSRs)		0	13
Servicing Assets at Fair Value, Purchased		0	0
Due to changes in inputs or assumptions	[3]	0	0
Servicing Asset at Fair Value, Other Changes in Fair Value	[4]	0	0
Servicing Asset at Fair Value, Disposals		0	$ 0
Commercial Mortgage Servicing Rights [Member]
Servicing Asset at Fair Value, Amount		62
Origination of Mortgage Servicing Rights (MSRs)		$ 62

[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] The majority of these other intangible assets acquired from Pillar relate to indefinite-lived agency licenses. See Note 2, "Acquisitions/Dispositions," for additional information.

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

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