Allowance for Loan and Lease Losses Allowance for Loan and Lease Losses - Loss Sharing Arrangements (Details) - Loss Sharing Agreement [Member] - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Collaborative Arrangements and Non-collaborative Arrangement Transactions [Line Items]
Reduction in Charge-offs due to loss sharing agreements	$ 52	$ 44
Reduction in provision for loan and lease losses	55	$ 57
Expected reimbursement netted in allowance for loan losses	$ 197		$ 194