Supplemental information to the Consolidated Statement of Cash Flows- Noncash Investing and Financing Transactions that are Not Reflected in Consolidated Statement of Cash Flows (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Supplemental Cash Flow Information [Abstract]
Transfers from loans to other assets for OREO	$ 1	$ 3
Assets of consolidated VIEs	245	262
Liabilities of consolidated VIEs	239	243
Noncontrolling interests of consolidated VIEs	27	39
Held-To-Maturity Securities Not Settled	$ 2,608	$ 0