Loans and Leases - Schedule of Activity In The Allowance For Loan Losses (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Allowance for Loan and Lease Losses [Roll Forward]
Beginning balance	$ 53	$ 46	$ 38
Provision for loan and lease losses	2	10	12
Charge-offs	(1)	(3)	(4)
Ending balance	$ 54	$ 53	$ 46