Loans Held for Investment portfolio and Related Allowance for Loan and Lease Losses (Detail) - USD ($) $ in Millions		Jun. 30, 2016	Mar. 31, 2016	Dec. 31, 2015	Jun. 30, 2015	Mar. 31, 2015	Dec. 31, 2014
Individually evaluated		$ 3,079		$ 2,876
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		286		287
Collectively evaluated		138,331		133,309
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		1,488		1,465
Total evaluated		141,410		136,185
Loans And Leases Receivable Allowance Loans Evaluated For Impairment Excluding Fair Value Loans		1,774		1,752
Loans Receivable, Fair Value Disclosure		246		257
Total	[1]	141,656		136,442
Loans and Leases Receivable, Allowance		1,774	$ 1,770	1,752	$ 1,834	$ 1,893	$ 1,937
Commercial Portfolio Segment [Member]
Individually evaluated		385		218
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		43		28
Collectively evaluated		77,063		75,034
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		1,104		1,019
Total evaluated		77,448		75,252
Loans And Leases Receivable Allowance Loans Evaluated For Impairment Excluding Fair Value Loans		1,147		1,047
Loans Receivable, Fair Value Disclosure		0		0
Total		77,448		75,252
Loans and Leases Receivable, Allowance		1,147	1,123	1,047	993	976	986
Residential Portfolio Segment [Member]
Individually evaluated		2,567		2,527
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		236		252
Collectively evaluated		36,636		36,144
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		203		282
Total evaluated		39,203		38,671
Loans And Leases Receivable Allowance Loans Evaluated For Impairment Excluding Fair Value Loans		439		534
Loans Receivable, Fair Value Disclosure		246		257
Total		39,449		38,928
Loans and Leases Receivable, Allowance		439	467	534	676	743	777
Consumer Portfolio Segment [Member]
Individually evaluated		127		131
Financing Receivable, Allowance for Credit Losses, Individually Evaluated for Impairment		7		7
Collectively evaluated		24,632		22,131
Financing Receivable, Allowance for Credit Losses, Collectively Evaluated for Impairment		181		164
Total evaluated		24,759		22,262
Loans And Leases Receivable Allowance Loans Evaluated For Impairment Excluding Fair Value Loans		188		171
Loans Receivable, Fair Value Disclosure		0		0
Total		24,759		22,262
Loans and Leases Receivable, Allowance		$ 188	$ 180	$ 171	$ 165	$ 174	$ 174

[1] Includes loans of consolidated VIEs of $227 million and $246 million at June 30, 2016 and December 31, 2015, respectively.