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
	Mar. 31, 2013		Mar. 31, 2012	Dec. 31, 2012
Principal Balance	$ 226,775	[1]		$ 228,114	[1]
Past Due	4,255	[2]		4,538	[2]
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	234		429
Loans
Principal Balance	120,804	[1]		121,470	[1]
Past Due	2,290	[2]		2,329	[2]
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	226		422
Loans | Commercial Portfolio Segment [Member]
Principal Balance	59,238	[1]		58,888	[1]
Past Due	309	[2]		320	[2]
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	45		101
Loans | Residential Portfolio Segment [Member]
Principal Balance	42,281	[1]		43,199	[1]
Past Due	1,856	[2]		1,941	[2]
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	156		297
Loans | Consumer Portfolio Segment [Member]
Principal Balance	19,285	[1]		19,383	[1]
Past Due	125	[2]		68	[2]
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	25		24
Managed Securitized Loans | Commercial Portfolio Segment [Member]
Principal Balance	1,731	[1]		1,767	[1]
Past Due	29	[2]		23	[2]
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	0		0
Managed Securitized Loans | Residential Portfolio Segment [Member]
Principal Balance	104,240	[1]		104,877	[1]
Past Due	1,936	[2],[3]		2,186	[2],[3]
Net Credit Losses During Period on Loans Managed or Securitized or Asset-backed Financing Arrangement	$ 8		$ 7

[1] Excludes $3.2 billion and $3.4 billion of LHFS at March 31, 2013 and December 31, 2012, respectively.

[2] Excludes $43 million and $38 million of past due LHFS at March 31, 2013 and December 31, 2012, respectively.

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