Expected Loss to be Paid - Key Assumptions in Base Case Expected Loss Second Lien RMBS (Details)	12 Months Ended
	Dec. 31, 2013		Dec. 31, 2012		Dec. 31, 2011
HELOCs
Guarantor Obligations [Line Items]
Expected period until final CDR	34 months	[1]	36 months	[1]	36 months	[1]
Final CPR	10.00%	[1]	10.00%	[1]	10.00%	[1]
Loss severity	98.00%	[1]	98.00%	[1]	98.00%	[1]
HELOCs | Minimum
Guarantor Obligations [Line Items]
Plateau CDR	2.30%	[1]	3.80%	[1]	4.00%	[1]
Final CDR trended down to	0.40%	[1]	0.40%	[1]	0.40%	[1]
Initial CPR	2.70%	[1]	2.90%	[1]	1.40%	[1]
HELOCs | Maximum
Guarantor Obligations [Line Items]
Plateau CDR	7.70%	[1]	15.90%	[1]	27.40%	[1]
Final CDR trended down to	3.20%	[1]	3.20%	[1]	3.20%	[1]
Initial CPR	21.50%	[1]	15.40%	[1]	25.80%	[1]
Closed-end second lien
Guarantor Obligations [Line Items]
Expected period until final CDR	34 months	[1]	36 months	[1]	36 months	[1]
Final CPR	10.00%	[1]	10.00%	[1]	10.00%	[1]
Loss severity	98.00%	[1]	98.00%	[1]	98.00%	[1]
Closed-end second lien | Minimum
Guarantor Obligations [Line Items]
Plateau CDR	7.30%	[1]	7.30%	[1]	6.90%	[1]
Final CDR trended down to	3.50%	[1]	3.50%	[1]	3.50%	[1]
Initial CPR	3.10%	[1]	1.90%	[1]	0.90%	[1]
Closed-end second lien | Maximum
Guarantor Obligations [Line Items]
Plateau CDR	15.10%	[1]	20.70%	[1]	29.50%	[1]
Final CDR trended down to	9.10%	[1]	9.10%	[1]	9.10%	[1]
Initial CPR	12.00%	[1]	12.50%	[1]	14.70%	[1]

[1] Represents variables for most heavily weighted scenario (the “base case”).