Goodwill and Other Intangible Assets - Changes in the Carrying Amounts of Other Intangible Assets (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
Beginning Balance	$ 1,017		$ 1,571
Amortization	(11)		(11)
MSRs originated	83		88
Changes in fair value:
Due to changes in inputs or assumptions	124	[1]	70	[1]
Due to fair value election	(57)	[2]	(52)	[2]
Sale of MSRs	(1)		(7)
Ending Balance	1,155		1,659
Core Deposits
Beginning Balance	38		67
Amortization	(6)		(8)
MSRs originated	0		0
Changes in fair value:
Due to changes in inputs or assumptions	0		0
Due to fair value election	0		0
Sale of MSRs			0
Other	0
Ending Balance	32		59
Mortgage Servicing Rights, Amortized Cost
Beginning Balance	921		1,439
Amortization	0		0
MSRs originated	83		88
Changes in fair value:
Due to changes in inputs or assumptions	124	[1]	70	[1]
Due to fair value election	(57)	[2]	(52)	[2]
Sale of MSRs			(7)
Other	(1)
Ending Balance	1,070		1,538
Other Intangible Assets
Beginning Balance	58		65
Amortization	(5)		(3)
MSRs originated	0		0
Changes in fair value:
Due to changes in inputs or assumptions	0		0
Due to fair value election	0		0
Sale of MSRs			0
Other	0
Ending Balance	$ 53		$ 62

[1] Primarily reflects changes in discount rates and prepayment speed assumptions, due to changes in interest rates.

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