Loans - Schedule of Additional Information on Nonaccrual Loans (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2016	Mar. 31, 2015	Dec. 31, 2015
Receivables [Abstract]
Residential Mortgage Loan Nonaccrual Carried At Lower Of Amortized Cost Or Fair Value Less Cost To Sell	$ 451		$ 768
Interest income that would have been recorded if the nonaccrual receivable had been current in accordance with contractual terms during the period	21	$ 21
Interest income that was recorded on nonaccrual loans and included in interest income during the period	$ 6	$ 6