Receivables Held for Sale - Additional Information (Detail) - USD ($)		1 Months Ended	3 Months Ended
		Apr. 30, 2016	Jun. 30, 2016	Mar. 31, 2016	Mar. 31, 2015
Financing Receivable, Recorded Investment, Past Due [Line Items]
Aggregate unpaid balance				$ 282,000,000	$ 431,000,000
Aggregate carrying value				267,000,000	311,000,000
Initial lower of amortized cost or fair value adjustment(2)				17,000,000	0
Provision for Credit Losses [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Initial lower of amortized cost or fair value adjustment(2)	[1]			13,000,000
Other Revenue [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Initial lower of amortized cost or fair value adjustment(2)	[2]			4,000,000
Subsequent to initial transfer to held for sale				51,000,000	17,000,000
Fair Value [Member] | Provision for Credit Losses [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Initial lower of amortized cost or fair value adjustment(2)	[1]			13,000,000
Fair Value [Member] | Other Revenue [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Initial lower of amortized cost or fair value adjustment(2)	[2]			4,000,000
Subsequent to initial transfer to held for sale				$ 68,000,000	$ 0
First Mortgage [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Threshold, days past due to initiate sale activities for first lien real estate secured receivables				180 days
Real Estate Secured Receivables Held for Sale [Member] | Subsequent Event [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Aggregate unpaid balance prior to sale		$ 1,421,000,000
Aggregate carrying value prior to sale		1,273,000,000
Aggregate cash consideration received		$ 1,440,000,000
Scenario, Forecast [Member] | Real Estate Secured Receivables Held for Sale [Member]
Financing Receivable, Recorded Investment, Past Due [Line Items]
Gain on sale of real estate secured receivables			$ 155,000,000

[1] Represents the portion of the initial lower of amortized cost or fair value adjustment attributable to credit factors which was recorded as provision for credit losses in the consolidated statement of income (loss) as there was no objective, verifiable evidence to indicate non-credit factors were associated with the decline in fair value.

[2] Represents the portion of the initial lower of amortized cost or fair value adjustment attributable to non-credit factors which was 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.