Activity in the Allowance for Credit Losses (Detail) (USD $) In Millions	3 Months Ended				9 Months Ended
	Sep. 30, 2011		Sep. 30, 2010		Sep. 30, 2011		Sep. 30, 2010		Jun. 30, 2011	Dec. 31, 2010	Jun. 30, 2010	Dec. 31, 2009
Components:
Balance at beginning of period	$ 2,795		$ 3,216		$ 3,032		$ 3,235
Provision for loan losses	348		620		1,194		2,199
Benefit for unfunded commitments	(1)		(5)		(8)		(60)
Loan charge-offs	(536)		(725)		(1,714)		(2,355)
Loan recoveries	44		35		146		122
Balance at end of period	2,650		3,141		2,650		3,141
ALLL	2,600		3,086		2,600		3,086		2,744	2,974	3,156	3,120
Unfunded commitments reserve	50	[1]	55	[1]	50	[1]	55	[1]
Allowance for credit losses	$ 2,650		$ 3,141		$ 2,650		$ 3,141

[1] The unfunded commitments reserve is separately recorded in other liabilities in the Consolidated Balance Sheets.