Receivables Held for Sale - Summary of Components of Cumulative Lower of Amortized Cost or Fair Value Adjustment (Detail) - USD ($)		3 Months Ended			9 Months Ended
		Sep. 30, 2017		Sep. 30, 2016	Sep. 30, 2017		Sep. 30, 2016
Lower of amortized cost or fair value adjustment recorded as a component of:
Initial lower of amortized cost or fair value adjustment				$ 562,000,000			$ 587,000,000
Lower of amortized cost or fair value adjustment on loans held for sale		$ 16,000,000		565,000,000	$ (155,000,000)		695,000,000
Fair Value [Member]
Lower of amortized cost or fair value adjustment recorded as a component of:
Lower of amortized cost or fair value adjustment on loans held for sale		10,000,000		577,000,000	(153,000,000)		732,000,000
Settlement [Member]
Lower of amortized cost or fair value adjustment recorded as a component of:
Lower of amortized cost or fair value adjustment on loans held for sale	[1]	6,000,000		(12,000,000)	(2,000,000)		(37,000,000)
Other Revenue [Member]
Lower of amortized cost or fair value adjustment recorded as a component of:
Initial lower of amortized cost or fair value adjustment	[2]			5,000,000			11,000,000
Subsequent to initial transfer to held for sale				3,000,000			108,000,000
Lower of amortized cost or fair value adjustment on loans held for sale		16,000,000	[3]	8,000,000	(155,000,000)	[3]	119,000,000
Other Revenue [Member] | Fair Value [Member]
Lower of amortized cost or fair value adjustment recorded as a component of:
Initial lower of amortized cost or fair value adjustment	[2]			5,000,000			11,000,000
Subsequent to initial transfer to held for sale				15,000,000			145,000,000
Lower of amortized cost or fair value adjustment on loans held for sale		10,000,000	[3]	20,000,000	(153,000,000)	[3]	156,000,000
Other Revenue [Member] | Settlement [Member]
Lower of amortized cost or fair value adjustment recorded as a component of:
Initial lower of amortized cost or fair value adjustment	[1],[2]			0			0
Subsequent to initial transfer to held for sale	[1]			(12,000,000)			(37,000,000)
Lower of amortized cost or fair value adjustment on loans held for sale	[1]	$ 6,000,000	[3]	(12,000,000)	$ (2,000,000)	[3]	(37,000,000)
Provision for Credit Losses [Member]
Lower of amortized cost or fair value adjustment recorded as a component of:
Initial lower of amortized cost or fair value adjustment	[4]			557,000,000			576,000,000
Provision for Credit Losses [Member] | Fair Value [Member]
Lower of amortized cost or fair value adjustment recorded as a component of:
Initial lower of amortized cost or fair value adjustment	[4]			557,000,000			576,000,000
Provision for Credit Losses [Member] | Settlement [Member]
Lower of amortized cost or fair value adjustment recorded as a component of:
Initial lower of amortized cost or fair value adjustment	[1],[4]			$ 0			$ 0

[1] Reflects receivable settlements due to either receivable charge-off or payoff (including short sales) or transfer of receivables to REO and reflects either a reversal of the non-credit fair value adjustment previously recorded on these receivables or an additional lower of amortized cost or fair value adjustment required at the time of settlement.

[2] Represents the portion of the initial lower of amortized cost or fair value adjustment attributable to non-credit factors which are recorded as a component of total other revenues in the consolidated statement income (loss) as it reflects the impact on value caused by current marketplace conditions including changes in interest rates.

[3] As all of our receivables are classified as held for sale at September 30, 2017 and December 31, 2016, for the three and nine months ended September 30, 2017 and for all future periods, any lower of amortized cost or fair value adjustments will relate to either changes in fair value subsequent to classification as held for sale or settlements of receivables as discussed above.

[4] Represents the portion of the initial lower of amortized cost or fair value adjustment attributable to credit factors which are recorded as provision for credit losses in the consolidated statement of income (loss).