Allowances for Loan and Lease Losses and Unfunded Loan Commitments and Letters Of Credit (Rollforward of Allowance for Unfunded Loan Commitments and Letters of Credit) (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Allowance For Loan And Lease Losses [Abstract]
Beginning balance	$ 242	$ 250
Net change in allowance for unfunded loan commitments and letters of credit	9	(15)
Ending balance	$ 251	$ 235