Loans Held for Investment portfolio and Related Allowance for Loan and Lease Losses (Detail) - USD ($) $ in Millions		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Individually evaluated		$ 2,876	$ 2,781
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		287	319
Collectively evaluated		133,309	130,059
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		1,465	1,618
Total evaluated		136,185	132,840
Loans And Leases Receivable Allowance Loans Evaluated For Impairment Excluding Fair Value Loans		1,752	1,937
Loans Receivable, Fair Value Disclosure		257	272
Total	[1]	136,442	133,112
Loans and Leases Receivable, Allowance		1,752	1,937	$ 2,044
Commercial Portfolio Segment [Member]
Individually evaluated		218	92
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		28	11
Collectively evaluated		75,034	73,300
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		1,019	975
Total evaluated		75,252	73,392
Loans And Leases Receivable Allowance Loans Evaluated For Impairment Excluding Fair Value Loans		1,047	986
Loans Receivable, Fair Value Disclosure		0	0
Total		75,252	73,392
Loans and Leases Receivable, Allowance		1,047	986	946
Residential Portfolio Segment [Member]
Individually evaluated		2,527	2,563
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		252	300
Collectively evaluated		36,144	35,940
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		282	477
Total evaluated		38,671	38,503
Loans And Leases Receivable Allowance Loans Evaluated For Impairment Excluding Fair Value Loans		534	777
Loans Receivable, Fair Value Disclosure		257	272
Total		38,928	38,775
Loans and Leases Receivable, Allowance		534	777	930
Consumer Portfolio Segment [Member]
Individually evaluated		131	126
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		7	8
Collectively evaluated		22,131	20,819
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		164	166
Total evaluated		22,262	20,945
Loans And Leases Receivable Allowance Loans Evaluated For Impairment Excluding Fair Value Loans		171	174
Loans Receivable, Fair Value Disclosure		0	0
Total		22,262	20,945
Loans and Leases Receivable, Allowance		$ 171	$ 174	$ 168

[1] Includes loans of consolidated VIEs of $246 million and $288 million at December 31, 2015 and December 31, 2014, respectively.