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			6 Months Ended
	Jun. 30, 2015		Jun. 30, 2014	Jun. 30, 2015		Jun. 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	$ 245		$ 721	$ 317		$ 712
R&W development and accretion of discount during period	4		19	(47)		67
R&W recovered during period	(26)		(89)	(47)		(128)
Future net R&W benefit at the end of the period	225	[1]	651	225	[1]	651
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	162		570	232		569
R&W development and accretion of discount during period	2		10	(48)		49
R&W recovered during period	(23)		(71)	(43)		(109)
Future net R&W benefit at the end of the period	142	[1]	509	142	[1]	509
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		0	(1)		(1)
R&W recovered during period	0		0	0		0
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	94		269	106		274
R&W development and accretion of discount during period	0		(2)	(10)		1
R&W recovered during period	(1)		(4)	(3)		(12)
Future net R&W benefit at the end of the period	93	[1]	263	93	[1]	263
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	(20)		152	15		173
R&W development and accretion of discount during period	6		11	(14)		20
R&W recovered during period	(19)		(19)	(34)		(49)
Future net R&W benefit at the end of the period	(33)	[1]	144	(33)	[1]	144
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	87		146	109		118
R&W development and accretion of discount during period	(4)		1	(23)		29
R&W recovered during period	(3)		(48)	(6)		(48)
Future net R&W benefit at the end of the period	81	[1]	99	81	[1]	99
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		151	85		143
R&W development and accretion of discount during period	2		9	1		18
R&W recovered during period	(3)		(18)	(4)		(19)
Future net R&W benefit at the end of the period	83	[1]	142	83	[1]	142
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		95	85		98
R&W development and accretion of discount during period	2		0	1		(3)
R&W recovered during period	(3)		(2)	(4)		(2)
Future net R&W benefit at the end of the period	83	[1]	93	83	[1]	93
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		56	0		45
R&W development and accretion of discount during period	0		9	0		21
R&W recovered during period	0		(16)	0		(17)
Future net R&W benefit at the end of the period	0	[1]	$ 49	$ 0	[1]	$ 49
Radian [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	2
Radian [Member] | 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	1
Radian [Member] | 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	0
Radian [Member] | 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	0
Radian [Member] | 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	0
Radian [Member] | 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	1
Radian [Member] | 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	1
Radian [Member] | 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	1
Radian [Member] | 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

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