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	6 Months Ended
	Jun. 30, 2015	Jun. 30, 2014
Allowance For Loan And Lease Losses [Abstract]
Beginning balance	$ 259	$ 242
Net change in allowance for unfunded loan commitments and letters of credit	(13)	(10)
Ending balance	$ 246	$ 232