Carrying Value of Those Assets Measured at Fair Value on a Non-Recurring Basis (Detail) (Fair Value, Measurements, Nonrecurring, USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Fair Value, Inputs, Level 2 | Loans Held-for-Sale
Assets measured at fair value on a non-recurring basis	$ 501	$ 142
Fair Value, Inputs, Level 2 | Loans Held-for-Investment
Assets measured at fair value on a non-recurring basis	0	0
Fair Value, Inputs, Level 2 | Other Real Estate Owned
Assets measured at fair value on a non-recurring basis	358	553
Fair Value, Inputs, Level 2 | Affordable Housing
Assets measured at fair value on a non-recurring basis		0
Fair Value, Inputs, Level 2 | Other Assets
Assets measured at fair value on a non-recurring basis	28	90
Fair Value, Inputs, Level 3 | Loans Held-for-Sale
Assets measured at fair value on a non-recurring basis	66	191
Fair Value, Inputs, Level 3 | Loans Held-for-Investment
Assets measured at fair value on a non-recurring basis	144	85
Fair Value, Inputs, Level 3 | Other Real Estate Owned
Assets measured at fair value on a non-recurring basis	151	43
Fair Value, Inputs, Level 3 | Affordable Housing
Assets measured at fair value on a non-recurring basis		357
Fair Value, Inputs, Level 3 | Other Assets
Assets measured at fair value on a non-recurring basis	15	40
Valuation Allowance | Loans Held-for-Sale
Valuation Allowance	1	0
Valuation Allowance | Loans Held-for-Investment
Valuation Allowance	16	(15)
Valuation Allowance | Other Real Estate Owned
Valuation Allowance	(126)	(116)
Valuation Allowance | Affordable Housing
Valuation Allowance		0
Valuation Allowance | Other Assets
Valuation Allowance	(14)	(20)
Fair Value, Inputs, Level 1 [Member] | Loans Held-for-Sale
Assets measured at fair value on a non-recurring basis	0	0
Fair Value, Inputs, Level 1 [Member] | Loans Held-for-Investment
Assets measured at fair value on a non-recurring basis	0	0
Fair Value, Inputs, Level 1 [Member] | Other Real Estate Owned
Assets measured at fair value on a non-recurring basis	0	0
Fair Value, Inputs, Level 1 [Member] | Affordable Housing
Assets measured at fair value on a non-recurring basis		0
Fair Value, Inputs, Level 1 [Member] | Other Assets
Assets measured at fair value on a non-recurring basis	0	0
Loans Held-for-Sale
Assets measured at fair value on a non-recurring basis	567	333
Loans Held-for-Investment
Assets measured at fair value on a non-recurring basis	144	85
Other Real Estate Owned
Assets measured at fair value on a non-recurring basis	509	596
Affordable Housing
Assets measured at fair value on a non-recurring basis		357
Other Assets
Assets measured at fair value on a non-recurring basis	$ 43	$ 130