Asset Quality - Allowance for Loan and Lease Losses (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Disclosure Asset Quality Allowance For Loan And Lease Losses [Abstract]
Balance at beginning of period - continuing operations	$ 888	$ 1,004
Charge-offs	(90)	(132)
Recoveries	41	31
Net loans and leases charged off	(49)	(101)
Provision for loan and lease losses from continuing operations	55	42
Foreign currency translation adjustment	(1)	(1)
Balance at end of period - continuing operations	$ 893	$ 944