Loans Held for Investment portfolio and Related Allowance for Loan and Lease Losses (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Individually evaluated	$ 3,078		$ 3,592
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	364		448
Collectively evaluated	118,013		118,470
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	1,810		2,009
Total evaluated	121,091		122,062
Loans And Leases Receivable Allowance Loans Evaluated For Impairment Excluding Fair Value Loans	2,174		2,457
Loans carried at fair value	379	[1]	433	[1]
Total	121,470	[1]	122,495	[1]
Loans and Leases Receivable, Allowance	2,174		2,457		2,974
Commercial Portfolio Segment [Member]
Individually evaluated	138		412
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	7		34
Collectively evaluated	58,750		55,458
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	895		930
Total evaluated	58,888		55,870
Loans And Leases Receivable Allowance Loans Evaluated For Impairment Excluding Fair Value Loans	902		964
Loans carried at fair value	0		2
Total	58,888		55,872
Loans and Leases Receivable, Allowance	902		964		1,303
Residential Portfolio Segment [Member]
Individually evaluated	2,859		3,141
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	348		405
Collectively evaluated	39,961		43,088
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	783		949
Total evaluated	42,820		46,229
Loans And Leases Receivable Allowance Loans Evaluated For Impairment Excluding Fair Value Loans	1,131		1,354
Loans carried at fair value	379		431
Total	43,199		46,660
Loans and Leases Receivable, Allowance	1,131		1,354		1,498
Consumer Portfolio Segment [Member]
Individually evaluated	81		39
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment	9		9
Collectively evaluated	19,302		19,924
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment	132		130
Total evaluated	19,383		19,963
Loans And Leases Receivable Allowance Loans Evaluated For Impairment Excluding Fair Value Loans	141		139
Loans carried at fair value	0		0
Total	19,383		19,963
Loans and Leases Receivable, Allowance	$ 141		$ 139		$ 173

[1] 2 Includes loans of consolidated VIEs365 3,322