Summary of Transactions in the ALLL by Portfolio segment (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2014		Sep. 30, 2013	Sep. 30, 2014		Sep. 30, 2013
Financing Receivable, Allowance for Credit Losses
Beginning Balance	$ 1,458		$ 1,735	$ 1,582	[1]	$ 1,854
Losses charged off	(146)		(141)	(464)		(454)
Recoveries of losses previously charged off	31		32	80		101
Provision for loan and lease losses	71		51	216		176
Ending Balance	1,414	[1]	1,677	1,414	[1]	1,677
Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Losses
Beginning Balance	961		1,183	1,058	[2]	1,236
Losses charged off	(72)		(61)	(236)		(189)
Recoveries of losses previously charged off	17		17	31		46
Provision for loan and lease losses	7		8	60		54
Ending Balance	913	[3]	1,147	913	[3]	1,147
Residential Mortgage Loans
Financing Receivable, Allowance for Credit Losses
Beginning Balance	174		201	189	[2]	229
Losses charged off	(12)		(15)	(41)		(55)
Recoveries of losses previously charged off	3		3	10		8
Provision for loan and lease losses	(1)		5	6		12
Ending Balance	164	[3]	194	164	[3]	194
Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Losses
Beginning Balance	221		247	225	[2]	278
Losses charged off	(62)		(65)	(187)		(210)
Recoveries of losses previously charged off	11		12	39		47
Provision for loan and lease losses	68		41	161		120
Ending Balance	238	[3]	235	238	[3]	235
Unallocated
Financing Receivable, Allowance for Credit Losses
Beginning Balance	102		104	110	[2]	111
Provision for loan and lease losses	(3)		(3)	(11)		(10)
Ending Balance	$ 99	[3]	$ 101	$ 99	[3]	$ 101

[1] Includes $150 and $49 of cash and due from banks, $48 and $48 of commercial mortgage loans, $2,785 and $1,010 of automobile loans, $(19) and $(15) of ALLL, $26 and $13 of other assets, $7 and $1 of other liabilities, and $2,882 and $1,048 of long-term debt from consolidated VIEs that are included in their respective captions above at September 30, 2014 and December 31, 2013, respectively. See Note 10.

[2] Includes $9 related to leveraged leases.

[3] Includes $7 related to leveraged leases.