Loans - Schedule of Additional Information on Nonaccrual Loans (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2016	Jun. 30, 2015	Jun. 30, 2016	Jun. 30, 2015	Dec. 31, 2015
Receivables [Abstract]
Residential Mortgage Loan Nonaccrual Carried At Lower Of Amortized Cost Or Fair Value Less Cost To Sell	$ 428		$ 428		$ 768
Interest income that would have been recorded if the nonaccrual receivable had been current in accordance with contractual terms during the period	19	$ 23	40	$ 44
Interest income that was recorded on nonaccrual loans and included in interest income during the period	$ 3	$ 6	$ 9	$ 12