Loans and Leases Loans and Leases (Schedule of Activity In The Allowance For Loan Losses) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 22	$ 22
Provisions	1	0
Recoveries	(1)	0
Ending balance	22	22
Institutional
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	22	22
Provisions	0	0
Recoveries	0	0
Ending balance	22	22
Commercial Real Estate
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	0	0
Provisions	1	0
Recoveries	(1)	0
Ending balance	$ 0	$ 0