Summary of Transactions in the ALLL by Portfolio Segment (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015		Dec. 31, 2014		Dec. 31, 2013
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	$ 1,322	[1]	$ 1,582		$ 1,854
Losses charged off	(542)		(679)		(637)
Recoveries of losses previously charged off	96		104		136
Provision for loan and lease losses	396		315		229
Ending Balance	1,272	[1]	1,322	[1]	1,582
Commercial Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	875	[2]	1,058		1,236
Losses charged off	(298)		(299)		(284)
Recoveries of losses previously charged off	37		38		64
Provision for loan and lease losses	226		78		42
Ending Balance	840		875	[2]	1,058
Residential Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	104	[2]	189		229
Losses charged off	(28)		(139)		(70)
Recoveries of losses previously charged off	11		13		10
Provision for loan and lease losses	13		41		20
Ending Balance	100		104	[2]	189
Consumer Portfolio Segment
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	237	[2]	225		278
Losses charged off	(216)		(241)		(283)
Recoveries of losses previously charged off	48		53		62
Provision for loan and lease losses	148		200		168
Ending Balance	217		237	[2]	225
Unallocated
Financing Receivable, Allowance for Credit Losses [Line Items]
Beginning Balance	106	[2]	110		111
Provision for loan and lease losses	9		(4)		(1)
Ending Balance	$ 115		$ 106	[2]	$ 110

[1] Includes $152 and $179 of cash and due from banks, $2,537 and $3,378 of portfolio loans and leases, $(28) and $(22) of ALLL, $20 and $25 of other assets, $3 and $5 of other liabilities and $2,493 and $3,434 of long-term debt from consolidated VIEs that are included in their respective captions above at December 31, 2015 and 2014, respectively. For further information, refer to Note 11.

[2] Includes $6 related to leveraged leases at December 31, 2014.