Fair Value Measurements - Carrying and Estimated Fair Value (Detail) - USD ($) $ in Millions		Sep. 30, 2015	Dec. 31, 2014
Financial assets:
Cash		$ 131	$ 157
Interest bearing deposits with banks		1,503	2,000
Securities purchased under agreements to resell		531	3,863
Financial liabilities:
Long-term debt		12,206	16,427
Level 1 [Member]
Financial assets:
Cash		131	157
Interest bearing deposits with banks		1,503	2,000
Securities purchased under agreements to resell		0	0
Real estate secured receivables:
Total real estate secured receivables	[1]	0	0
Real estate secured receivables held for sale		0	0
Due from affiliates		0	0
Financial liabilities:
Due to affiliates carried at fair value		0	0
Due to affiliates not carried at fair value		0	0
Level 1 [Member] | First lien [Member]
Real estate secured receivables:
Total real estate secured receivables	[1]	0	0
Level 1 [Member] | Second lien [Member]
Real estate secured receivables:
Total real estate secured receivables	[1]	0	0
Level 2 [Member]
Financial assets:
Cash		0	0
Interest bearing deposits with banks		0	0
Securities purchased under agreements to resell		531	3,863
Real estate secured receivables:
Total real estate secured receivables	[1]	0	0
Real estate secured receivables held for sale		1,635	0
Due from affiliates		127	102
Financial liabilities:
Due to affiliates carried at fair value		505	512
Due to affiliates not carried at fair value		4,661	6,723
Level 2 [Member] | First lien [Member]
Real estate secured receivables:
Total real estate secured receivables	[1]	0	0
Level 2 [Member] | Second lien [Member]
Real estate secured receivables:
Total real estate secured receivables	[1]	0	0
Level 3 [Member]
Financial assets:
Cash		0	0
Interest bearing deposits with banks		0	0
Securities purchased under agreements to resell		0	0
Real estate secured receivables:
Total real estate secured receivables	[1]	8,741	18,124
Real estate secured receivables held for sale		8,752	937
Due from affiliates		0	0
Financial liabilities:
Due to affiliates carried at fair value		0	0
Due to affiliates not carried at fair value		0	0
Level 3 [Member] | First lien [Member]
Real estate secured receivables:
Total real estate secured receivables	[1]	7,558	16,878
Level 3 [Member] | Second lien [Member]
Real estate secured receivables:
Total real estate secured receivables	[1]	1,183	1,246
Carrying Value [Member]
Financial assets:
Cash		131	157
Interest bearing deposits with banks		1,503	2,000
Securities purchased under agreements to resell		531	3,863
Real estate secured receivables:
Total real estate secured receivables	[1]	9,434	21,242
Real estate secured receivables held for sale		10,041	860
Due from affiliates		127	102
Financial liabilities:
Due to affiliates carried at fair value		505	512
Due to affiliates not carried at fair value		4,431	6,433
Carrying Value [Member] | First lien [Member]
Real estate secured receivables:
Total real estate secured receivables	[1]	7,596	18,943
Carrying Value [Member] | Second lien [Member]
Real estate secured receivables:
Total real estate secured receivables	[1]	1,838	2,299
Estimated Fair Value [Member]
Financial assets:
Cash		131	157
Interest bearing deposits with banks		1,503	2,000
Securities purchased under agreements to resell		531	3,863
Real estate secured receivables:
Total real estate secured receivables	[1]	8,741	18,124
Real estate secured receivables held for sale		10,387	937
Due from affiliates		127	102
Financial liabilities:
Due to affiliates carried at fair value		505	512
Due to affiliates not carried at fair value		4,661	6,723
Estimated Fair Value [Member] | First lien [Member]
Real estate secured receivables:
Total real estate secured receivables	[1]	7,558	16,878
Estimated Fair Value [Member] | Second lien [Member]
Real estate secured receivables:
Total real estate secured receivables	[1]	1,183	1,246
Long-term Debt Carried at Fair Value [Member] | Level 1 [Member]
Financial liabilities:
Long-term debt		0	0
Long-term Debt Carried at Fair Value [Member] | Level 2 [Member]
Financial liabilities:
Long-term debt		4,559	6,762
Long-term Debt Carried at Fair Value [Member] | Level 3 [Member]
Financial liabilities:
Long-term debt		0	0
Long-term Debt Carried at Fair Value [Member] | Carrying Value [Member]
Financial liabilities:
Long-term debt		4,559	6,762
Long-term Debt Carried at Fair Value [Member] | Estimated Fair Value [Member]
Financial liabilities:
Long-term debt		4,559	6,762
Long Term Debt Not Carried at Fair Value [Member] | Level 1 [Member]
Financial liabilities:
Long-term debt		0	0
Long Term Debt Not Carried at Fair Value [Member] | Level 2 [Member]
Financial liabilities:
Long-term debt		8,093	8,779
Long Term Debt Not Carried at Fair Value [Member] | Level 3 [Member]
Financial liabilities:
Long-term debt		0	1,454
Long Term Debt Not Carried at Fair Value [Member] | Carrying Value [Member]
Financial liabilities:
Long-term debt		7,647	9,665
Long Term Debt Not Carried at Fair Value [Member] | Estimated Fair Value [Member]
Financial liabilities:
Long-term debt		$ 8,093	$ 10,233

[1] The receivable balances included in this table reflects the principal amount outstanding on the loan net of any charge-off recorded in accordance with our existing charge-off policies and includes certain basis adjustments to the loan such as unearned income, unamortized deferred fees and costs on originated loans, purchase accounting fair value adjustments and premiums or discounts on purchased loans. However, these basis adjustments on the loans are excluded in other presentations of dollars of two-months-and-over contractual delinquency, nonaccrual receivable and nonperforming receivable account balances.