Loans and Leases (Carrying Value of Purchased Impaired and Nonimpaired Loans) (Details) (USD $) In Millions	Jun. 30, 2011		Dec. 31, 2010
Residential mortgage	$ 18,372		$ 17,550
Commercial real estate	2,689	[1]	3,397	[1]
Total covered	5,504		6,194
Other acquired	50		58
Purchased Impaired Loans [Member]
Residential mortgage	700		733
Commercial real estate	1,728		2,031
Commercial	89		91
Total covered	2,517		2,855
Other acquired	2		3
Total	2,519		2,858
Allowance for loan losses	(114)		(90)
Net	2,405		2,768
Purchased Nonimpaired Loans [Member]
Residential mortgage	678		713
Commercial real estate	1,826		1,982
Commercial	483		644
Total covered	2,987		3,339
Other acquired	48		55
Total	3,035		3,394
Allowance for loan losses	(45)		(54)
Net	2,990		3,340
Purchased Impaired and Nonimpaired Loans [Member]
Residential mortgage	1,378		1,446
Commercial real estate	3,554		4,013
Commercial	572		735
Total covered	5,504		6,194
Other acquired	50		58
Total	5,554		6,252
Allowance for loan losses	(159)		(144)
Net	$ 5,395		$ 6,108

[1] Commercial real estate—residential ADC represents residential acquisition, development and construction loans.