Asset Transfers in Which the Company has Continuing Economic Involvement (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended			3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended		3 Months Ended		6 Months Ended				3 Months Ended		6 Months Ended
	Jun. 30, 2012	Mar. 31, 2011	Jun. 30, 2012	Jun. 30, 2011	Dec. 31, 2011	Jun. 30, 2012 Residential Mortgage	Mar. 31, 2011 Residential Mortgage	Jun. 30, 2012 Residential Mortgage	Jun. 30, 2011 Residential Mortgage	Jun. 30, 2012 Commercial and Corporate Loans [Member]	Mar. 31, 2011 Commercial and Corporate Loans [Member]	Jun. 30, 2012 Commercial and Corporate Loans [Member]	Jun. 30, 2011 Commercial and Corporate Loans [Member]	Jun. 30, 2012 Collateralized Debt Obligations [Member]	Mar. 31, 2011 Collateralized Debt Obligations [Member]	Jun. 30, 2012 Collateralized Debt Obligations [Member]	Jun. 30, 2011 Collateralized Debt Obligations [Member]	Jun. 30, 2012 Variable Interest Entity, Not Primary Beneficiary [Member] Community Development Investments [Member]	Dec. 31, 2011 Variable Interest Entity, Not Primary Beneficiary [Member] Community Development Investments [Member]	Jun. 30, 2012 Variable Interest Entity, Not Primary Beneficiary [Member] Residential Mortgage	Jun. 30, 2011 Variable Interest Entity, Not Primary Beneficiary [Member] Residential Mortgage	Jun. 30, 2012 Variable Interest Entity, Not Primary Beneficiary [Member] Residential Mortgage	Jun. 30, 2011 Variable Interest Entity, Not Primary Beneficiary [Member] Residential Mortgage	Dec. 31, 2011 Variable Interest Entity, Not Primary Beneficiary [Member] Residential Mortgage	Jun. 30, 2012 Variable Interest Entity, Not Primary Beneficiary [Member] Commercial and Corporate Loans [Member]	Dec. 31, 2011 Variable Interest Entity, Not Primary Beneficiary [Member] Commercial and Corporate Loans [Member]	Jun. 30, 2012 General Partner [Member] Community Development Investments [Member]	Dec. 31, 2011 General Partner [Member] Community Development Investments [Member]	Jun. 30, 2012 Limited Partner Variable Interest Entity, Not Primary Beneficiary [Member] Community Development Investments [Member]	Dec. 31, 2011 Limited Partner Variable Interest Entity, Not Primary Beneficiary [Member] Community Development Investments [Member]
Assets	$ 178,257		$ 178,257		$ 176,859													$ 1,200	$ 1,200	$ 484		$ 484		$ 529	$ 1,900	$ 2,000	$ 5	$ 5
Variable Interest Entity, Reporting Entity Involvement, Maximum Loss Exposure, Amount																		106	108										454	472
Loans and Leases Receivable, Gain (Loss) on Sales, Net																				236	107	460	118
Cash flows on interests held	9	14	16	30		8	13	15	28	0	1	0	1	1	0	1	1
Servicing or management fees	$ 3	$ 3	$ 6	$ 7		$ 1	$ 1	$ 1	$ 2	$ 2	$ 2	$ 5	$ 5	$ 0	$ 0	$ 0	$ 0