Expected Loss to be Paid - Net Expected Recoveries from Breaches of R&W Rollforward (Details) - RMBS [Member] - United States [Member] - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2015		Sep. 30, 2014	Sep. 30, 2015		Sep. 30, 2014
Estimated Benefit From Recoveries From Breaches of R and W Net of Reinsurance [Roll Forward]
Future net R&W benefit at the beginning of the period	$ 225		$ 651	$ 317		$ 712
R&W development and accretion of discount during period	(1)		93	(48)		160
R&W recovered during period	(26)		(166)	(73)		(294)
Future net R&W benefit at the end of the period	198	[1]	578	198	[1]	578
First Lien [Member]
Estimated Benefit From Recoveries From Breaches of R and W Net of Reinsurance [Roll Forward]
Future net R&W benefit at the beginning of the period	142		509	232		569
R&W development and accretion of discount during period	0		35	(48)		84
R&W recovered during period	(25)		(163)	(68)		(272)
Future net R&W benefit at the end of the period	117	[1]	381	117	[1]	381
First Lien [Member] | Prime [Member]
Estimated Benefit From Recoveries From Breaches of R and W Net of Reinsurance [Roll Forward]
Future net R&W benefit at the beginning of the period	1		3	2		4
R&W development and accretion of discount during period	0		1	(1)		0
R&W recovered during period	0		(1)	0		(1)
Future net R&W benefit at the end of the period	1	[1]	3	1	[1]	3
First Lien [Member] | Alt-A [Member]
Estimated Benefit From Recoveries From Breaches of R and W Net of Reinsurance [Roll Forward]
Future net R&W benefit at the beginning of the period	93		263	106		274
R&W development and accretion of discount during period	9		19	(1)		20
R&W recovered during period	(2)		(79)	(5)		(91)
Future net R&W benefit at the end of the period	100	[1]	203	100	[1]	203
First Lien [Member] | Option ARM [Member]
Estimated Benefit From Recoveries From Breaches of R and W Net of Reinsurance [Roll Forward]
Future net R&W benefit at the beginning of the period	(33)		144	15		173
R&W development and accretion of discount during period	(5)		10	(19)		30
R&W recovered during period	(20)		(76)	(54)		(125)
Future net R&W benefit at the end of the period	(58)	[1]	78	(58)	[1]	78
First Lien [Member] | Subprime [Member]
Estimated Benefit From Recoveries From Breaches of R and W Net of Reinsurance [Roll Forward]
Future net R&W benefit at the beginning of the period	81		99	109		118
R&W development and accretion of discount during period	(4)		5	(27)		34
R&W recovered during period	(3)		(7)	(9)		(55)
Future net R&W benefit at the end of the period	74	[1]	97	74	[1]	97
Second Lien [Member]
Estimated Benefit From Recoveries From Breaches of R and W Net of Reinsurance [Roll Forward]
Future net R&W benefit at the beginning of the period	83		142	85		143
R&W development and accretion of discount during period	(1)		58	0		76
R&W recovered during period	(1)		(3)	(5)		(22)
Future net R&W benefit at the end of the period	81	[1]	197	81	[1]	197
Second Lien [Member] | Closed-end [Member]
Estimated Benefit From Recoveries From Breaches of R and W Net of Reinsurance [Roll Forward]
Future net R&W benefit at the beginning of the period	83		93	85		98
R&W development and accretion of discount during period	(1)		(1)	0		(4)
R&W recovered during period	(1)		(3)	(5)		(5)
Future net R&W benefit at the end of the period	81	[1]	89	81	[1]	89
Second Lien [Member] | HELOCs [Member]
Estimated Benefit From Recoveries From Breaches of R and W Net of Reinsurance [Roll Forward]
Future net R&W benefit at the beginning of the period	0		49	0		45
R&W development and accretion of discount during period	0		59	0		80
R&W recovered during period	0		0	0		(17)
Future net R&W benefit at the end of the period	$ 0	[1]	$ 108	$ 0	[1]	$ 108

[1] See the section "Breaches of Representations and Warranties" below for eligible assets held in trust.