Loans - Schedule of Additional Information on Nonaccrual Loans (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014	Dec. 31, 2014
Receivables [Abstract]
Residential Mortgage Loan Nonaccrual Carried At Lower Of Amortized Cost Or Fair Value Less Cost To Sell	$ 760		$ 817
Interest income that would have been recorded if the nonaccrual receivable had been current in accordance with contractual terms during the period	21	28
Interest income that was recorded on nonaccrual loans and included in interest income during the period	$ 6	$ 8