Asset Quality - Summary of Allowance for Loan and Lease Losses (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Financing Receivable, Recorded Investment [Line Items]
Beginning balance			$ 823	$ 887
Charge-offs			(177)	(196)
Recoveries			57	92
Provision for loan and lease losses from continuing operations	$ 45	$ 19	121	35
Foreign currency translation adjustment			(1)
Ending balance	813	835	813	835
Continuing Operations [Member]
Financing Receivable, Recorded Investment [Line Items]
Beginning balance	796	814	794	848
Charge-offs	(53)	(49)	(152)	(162)
Recoveries	12	18	47	81
Net loans and leases charged off	(41)	(31)	(105)	(81)
Provision for loan and lease losses from continuing operations	36	21	102	37
Foreign currency translation adjustment	(1)		(1)
Ending balance	$ 790	$ 804	$ 790	$ 804