Loans Held for Investment portfolio and Related Allowance for Loan and Lease Losses (Detail) - USD ($) $ in Millions		Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013
Individually evaluated		$ 2,691		$ 2,781
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		285		319
Collectively evaluated		129,584		130,059
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		1,549		1,618
Total evaluated		132,275		132,840
Loans And Leases Receivable Allowance Loans Evaluated For Impairment Excluding Fair Value Loans		1,834		1,937
Loans Receivable, Fair Value Disclosure		263		272
Total	[1]	132,538		133,112
Loans and Leases Receivable, Allowance		1,834	$ 1,893	1,937	$ 2,003	$ 2,040	$ 2,044
Commercial Portfolio Segment [Member]
Individually evaluated		64		92
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		5		11
Collectively evaluated		73,237		73,300
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		988		975
Total evaluated		73,301		73,392
Loans And Leases Receivable Allowance Loans Evaluated For Impairment Excluding Fair Value Loans		993		986
Loans Receivable, Fair Value Disclosure		0		0
Total		73,301		73,392
Loans and Leases Receivable, Allowance		993	976	986	958	966	946
Residential Portfolio Segment [Member]
Individually evaluated		2,499		2,563
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		273		300
Collectively evaluated		35,974		35,940
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		403		477
Total evaluated		38,473		38,503
Loans And Leases Receivable Allowance Loans Evaluated For Impairment Excluding Fair Value Loans		676		777
Loans Receivable, Fair Value Disclosure		263		272
Total		38,736		38,775
Loans and Leases Receivable, Allowance		676	743	777	875	910	930
Consumer Portfolio Segment [Member]
Individually evaluated		128		126
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		7		8
Collectively evaluated		20,373		20,819
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		158		166
Total evaluated		20,501		20,945
Loans And Leases Receivable Allowance Loans Evaluated For Impairment Excluding Fair Value Loans		165		174
Loans Receivable, Fair Value Disclosure		0		0
Total		20,501		20,945
Loans and Leases Receivable, Allowance		$ 165	$ 174	$ 174	$ 170	$ 164	$ 168

[1] Includes loans of consolidated VIEs of $266 million and $288 million at June 30, 2015 and December 31, 2014, respectively.