Activity in the ALLL by segment (Detail) (USD $) In Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2011	Sep. 30, 2010	Sep. 30, 2011	Sep. 30, 2010
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	$ 2,744	$ 3,156	$ 2,974	$ 3,120
Provision for loan losses	348	620	1,194	2,199
Loan charge-offs	(536)	(725)	(1,714)	(2,355)
Loan recoveries	44	35	146	122
Balance at end of period	2,600	3,086	2,600	3,086
Commercial Portfolio Segment
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	1,200	1,447	1,303	1,353
Provision for loan losses	86	186	318	671
Loan charge-offs	(214)	(251)	(619)	(694)
Loan recoveries	29	20	99	72
Balance at end of period	1,101	1,402	1,101	1,402
Residential Mortgage Loans
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	1,395	1,538	1,498	1,592
Provision for loan losses	236	392	810	1,406
Loan charge-offs	(282)	(433)	(970)	(1,511)
Loan recoveries	3	5	14	15
Balance at end of period	1,352	1,502	1,352	1,502
Consumer Portfolio Segment
Allowance for Loan and Lease Losses [Roll Forward]
Balance at beginning of period	149	171	173	175
Provision for loan losses	26	42	66	122
Loan charge-offs	(40)	(41)	(125)	(150)
Loan recoveries	12	10	33	35
Balance at end of period	$ 147	$ 182	$ 147	$ 182