Receivables Held for Sale - Summary of Secured Receivables Transferred to REO or the Underlying Collateral Sold in a Short Sale (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015	Mar. 31, 2014
Transferred to REO after obtaining title to the underlying collateral [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Carrying value of real estate secured receivables held for sale settled through short sale or transfer to REO	$ 24	$ 70
Impact to lower of amortized cost or FV adjustment previously recorded resulting from the transfer to REO or short sales	0	4
Underlying collateral sold in a short sale [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Carrying value of real estate secured receivables held for sale settled through short sale or transfer to REO	11	11
Impact to lower of amortized cost or FV adjustment previously recorded resulting from the transfer to REO or short sales	$ 1	$ 1