Activity in the ALLL by segment (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2014	Jun. 30, 2013	Jun. 30, 2014	Jun. 30, 2013
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	$ 2,040	$ 2,152	$ 2,044	$ 2,174
Provision for loan losses	76	152	182	356
Loan charge-offs	(158)	(233)	(309)	(506)
Loan recoveries	45	54	86	101
Balance at end of period	2,003	2,125	2,003	2,125
Commercial Portfolio Segment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	966	921	946	902
Provision for loan losses	18	42	57	106
Loan charge-offs	(38)	(64)	(71)	(124)
Loan recoveries	12	20	26	35
Balance at end of period	958	919	958	919
Residential Portfolio Segment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	910	1,087	930	1,131
Provision for loan losses	32	78	80	190
Loan charge-offs	(90)	(143)	(175)	(321)
Loan recoveries	23	24	40	46
Balance at end of period	875	1,046	875	1,046
Consumer Portfolio Segment [Member]
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	164	144	168	141
Provision for loan losses	26	32	45	60
Loan charge-offs	(30)	(26)	(63)	(61)
Loan recoveries	10	10	20	20
Balance at end of period	$ 170	$ 160	$ 170	$ 160