Receivables Held for Sale - Summary of Activity in Receivables Held for Sale (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2015		Mar. 31, 2014		Dec. 31, 2014
Receivables Held for Sale, Activity [Roll Forward]
Receivables held for sale at beginning of period					$ 860	[1]
Receivables held for sale at end of period	1,097	[1]			860	[1]
Mortgage Loans on Real Estate [Member]
Receivables Held for Sale, Activity [Roll Forward]
Receivables held for sale at beginning of period	860		2,047
Lower of amortized cost or fair value adjustment on receivables held for sale	(17)		171
Carrying value of real estate secured receivables held for sale settled through short sale or transfer to REO	(35)		(81)
Change in real estate secured receivable balance, including collections	(7)		29
Transfer of real estate secured receivables into held for investment at the lower of amortized cost or fair value			(8)
Transfer of real estate secured receivables into held for sale at the lower of amortized cost or fair value	296	[2]	262	[2]
Receivables held for sale at end of period	$ 1,097	[3]	$ 2,420	[3]

[1] The receivable balances included in this table reflect the current carrying amount of the loan excluding certain basis adjustments to the loan such as deferred fees and costs on originated loans, purchase accounting fair value adjustments and premiums or discounts on purchased receivables.

[2] For the three months ended March 31, 2015, no initial lower of amortized cost or fair value adjustment was required for the receivables transferred to held for sale as the fair value of these receivables at the time of transfer exceeded the carrying value after consideration of credit loss reserves associated with these receivables. The initial lower of amortized cost or fair value adjustment on receivables transferred into held for sale during the three months ended March 31, 2014, totaled $60 million.

[3] The following table provides a rollforward of our valuation allowance for the three months ended March 31, 2015 and 2014. At March 31, 2015, the valuation allowance is zero as the fair value of the pool of receivables held for sale at March 31, 2015 exceeds the carrying value as these receivables are carried at the lower of amortized cost or fair value. See Note 13, "Fair Value Measurements," for a discussion of the factors impacting the fair value of these receivables.