Summary of Transactions in the ALLL by Portfolio segment (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014
Financing Receivable, Allowance for Credit Losses
Beginning Balance	$ 1,322	[1]	$ 1,582
Losses charged-off	(115)		(190)
Recoveries of losses previously charged- off	24		22
Provision for loan and lease losses	69		69
Ending Balance	1,300	[1]	1,483
Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Losses
Beginning Balance	875	[2]	1,058
Losses charged-off	(48)		(110)
Recoveries of losses previously charged- off	9		5
Provision for loan and lease losses	16		28
Ending Balance	852	[2]	981
Residential Mortgage Loans
Financing Receivable, Allowance for Credit Losses
Beginning Balance	104	[2]	189
Losses charged-off	(9)		(19)
Recoveries of losses previously charged- off	3		4
Provision for loan and lease losses	5		6
Ending Balance	103	[2]	180
Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Losses
Beginning Balance	237	[2]	225
Losses charged-off	(58)		(61)
Recoveries of losses previously charged- off	12		13
Provision for loan and lease losses	50		40
Ending Balance	241	[2]	217
Unallocated
Financing Receivable, Allowance for Credit Losses
Beginning Balance	106	[2]	110
Provision for loan and lease losses	(2)		(5)
Ending Balance	$ 104	[2]	$ 105

[1] Includes $176 and $179 of cash and due from banks, $48 and $47 of commercial mortgage loans, $2,900 and $3,331 of automobile loans, $(23) and $(22) of ALLL, $26 and $25 of other assets, $4 and $5 of other liabilities, and $2,983 and $3,434 of long-term debt from consolidated VIEs that are included in their respective captions above at March 31, 2015 and December 31, 2014, respectively. For further information refer to Note 10.

[2] Includes $6 related to leveraged leases.