Branch Assets and Liabilities Held for Sale - Assets and Liabilities Held for Sale for Certain Retail Branches (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2012		Dec. 31, 2011
Disclosure Branch Assets And Liabilities Held For Sale Assets And Liabilities Held For Sale For Certain Retail Branches [Abstract]
Loans held for sale	$ 0	[1]	$ 2,495	[1]
Other branch assets held for sale:
Properties and equipment, net	0		42
Goodwill allocated to retail branch disposal group	0		398
Total other branch assets held for sale	0		440
Total branch assets held for sale	0		2,935
Deposits held for sale	0		15,144
Other branch liabilities held for sale	0		11
Total branch liabilities held for sale	$ 0		$ 15,155

[1] Loans held for sale included $521 million of commercial loans, $1.4 billion of residential mortgages, $416 million of credit card loans and $161 million in other consumer loans at December 31, 2011.