Summary of Transactions in the ALLL by Portfolio segment (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2012		Mar. 31, 2011
Beginning Balance	$ 2,255	[1]	$ 3,004
Losses charged off	(253)		(397)
Recoveries of losses previously charged off	33		30
Provision for loan and lease losses	91		168
Ending Balance	2,126	[1]	2,805	[1]
Commercial Portfolio Segment
Beginning Balance	1,527	[2]	1,989
Losses charged off	(117)		(176)
Recoveries of losses previously charged off	15		12
Provision for loan and lease losses	(1)		30
Ending Balance	1,424	[2]	1,855	[2]
Residential Mortgage Loans
Beginning Balance	227	[2]	310
Losses charged off	(38)		(67)
Recoveries of losses previously charged off	1		2
Provision for loan and lease losses	43		41
Ending Balance	233	[2]	286	[2]
Consumer Portfolio Segment
Beginning Balance	365	[2]	555
Losses charged off	(98)		(154)
Recoveries of losses previously charged off	17		16
Provision for loan and lease losses	57		102
Ending Balance	341	[2]	519	[2]
Unallocated (Member)
Beginning Balance	136	[2]	150
Provision for loan and lease losses	(8)		(5)
Ending Balance	$ 128	[2]	$ 145	[2]

[1] Includes $19, $30 and $54 of cash, $4, $7 and $7of other short-term investments, $50, $50 and $29 of commercial mortgage loans, $217, $223 and $236 of home equity loans, $105, $259 and $529 of automobile loans, ($7), ($10) and ($12) of ALLL, $3, $4 and $5 of other assets, $3, $4 and $10 of other liabilities, $125, $191and $492 of long-term debt from consolidated VIEs that are included in their respective captions above at March 31, 2012, December 31, 2011 and March 31, 2011, respectively. See Note 8.

[2] Includes $14 related to leveraged leases.