Summary of Transactions in the ALLL by Portfolio segment (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011		Dec. 31, 2010		Dec. 31, 2009
Beginning Balance	$ 3,004	[1]	$ 3,749		$ 2,787
Losses charged off	(1,314)		(2,485)		(2,719)
Recoveries of losses previously charged off	142		157		138
Change In Accounting Principle			45
Provision for loan and lease losses	423		1,538		3,543
Ending Balance	2,255	[1]	3,004	[1]	3,749
Commercial Portfolio Segment
Beginning Balance	1,989	[2]	2,517
Losses charged off	(615)		(1,444)
Recoveries of losses previously charged off	61		80
Provision for loan and lease losses	92		836
Ending Balance	1,527	[3]	1,989	[2]
Residential Mortgage Loans
Beginning Balance	310	[2]	375
Losses charged off	(180)		(441)
Recoveries of losses previously charged off	7		2
Provision for loan and lease losses	90		374
Ending Balance	227	[3]	310	[2]
Consumer Portfolio Segment
Beginning Balance	555	[2]	664
Losses charged off	(519)		(600)
Recoveries of losses previously charged off	74		75
Change In Accounting Principle			45
Provision for loan and lease losses	255		371
Ending Balance	365	[3]	555	[2]
Unallocated (Member)
Beginning Balance	150	[2]	193
Provision for loan and lease losses	(14)		(43)
Ending Balance	$ 136	[3]	$ 150	[2]

[1] At December 31, 2011 and 2010, includes $30 and $52 of cash, $7 of other short-term investments, $50 and $29 of commercial mortgage loans, $223 and $241 of home equity loans, $259 and $648 of automobile loans, ($10) and ($14) of ALLL, $4 and $7 of other assets, $4 and $12 of other liabilities, $191 and $692 of long-term debt from consolidated VIEs that are included in their respective captions. See Note 11.

[2] Includes $15 related to leveraged leases.

[3] Includes $14 related to leveraged leases