Portfolio Balances and Delinquency Balances Based on 90 days or more Past Due and Net Charge-Offs Related to Managed Portfolio Loans (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2012		Sep. 30, 2011	Sep. 30, 2012		Sep. 30, 2011	Dec. 31, 2011
Principal Balance	$ 230,994			$ 230,994			$ 238,815
Past Due	5,278			5,278			8,284
Net Charge-offs	518		504	1,306		1,607
Loans
Principal Balance	121,817			121,817			122,495
Past Due	2,835			2,835			4,931
Net Charge-offs	511		492	1,283		1,568
Loans | Commercial Portfolio Segment [Member]
Principal Balance	57,706			57,706			55,872
Past Due	511			511			938
Net Charge-offs	71		185	235		520
Loans | Residential Portfolio Segment [Member]
Principal Balance	44,572			44,572			46,660
Past Due	1,985			1,985			3,079
Net Charge-offs	415		279	980		956
Loans | Consumer Portfolio Segment [Member]
Principal Balance	19,539			19,539			19,963
Past Due	339			339			914
Net Charge-offs	25		28	68		92
Managed Securitized Loans | Commercial Portfolio Segment [Member]
Principal Balance	1,785			1,785			1,978
Past Due	24			24			43
Net Charge-offs	0		0	0		0
Managed Securitized Loans | Residential Portfolio Segment [Member]
Principal Balance	107,392			107,392			114,342
Past Due	2,419	[1]		2,419	[1]		3,310	[1]
Net Charge-offs	$ 7		$ 12	$ 23		$ 39

[1] Excludes loans that have completed the foreclosure or short sale process (i.e., involuntary prepayments).