Expected Losses to be Paid (Roll Forward of Estimated Benefit From Recoveries) (Details 2) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2013		Mar. 31, 2012
Estimated Benefit From Recoveries From Breaches of R and W Net of Reinsurance [Roll Forward]
R&W development and accretion of discount during period	$ 157		$ 51
Gross R&W amounts recovered	92		77
Prime first lien
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	4		3
R&W development and accretion of discount during period	0		1
R&W recovered during period	0	[1]	0	[1]
Future net R&W benefit at the end of the period	4	[2]	4
Alt-A first lien
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	378		407
R&W development and accretion of discount during period	(8)		27
R&W recovered during period	(8)	[1]	(1)	[1]
Future net R&W benefit at the end of the period	362	[2]	433
First mortgage, option adjustable rate mortgage
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	591		725
R&W development and accretion of discount during period	153		28
R&W recovered during period	(54)	[1]	(18)	[1]
Future net R&W benefit at the end of the period	690	[2]	735
First mortgage, subprime
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	109		101
R&W development and accretion of discount during period	4		(5)
R&W recovered during period	0	[1]	0	[1]
Future net R&W benefit at the end of the period	113	[2]	96
Total first lien
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	1,082		1,236
R&W development and accretion of discount during period	149		51
R&W recovered during period	(62)	[1]	(19)	[1]
Future net R&W benefit at the end of the period	1,169	[2]	1,268
Closed end second lien and HELOCs
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	138		224
R&W development and accretion of discount during period	(9)		(2)
R&W recovered during period	(21)	[1]	0	[1]
Future net R&W benefit at the end of the period	108	[2]	222
HELOCs
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	150		190
R&W development and accretion of discount during period	17		2
R&W recovered during period	(6)	[1]	(51)	[1]
Future net R&W benefit at the end of the period	161	[2]	141
Second lien
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	288		414
R&W development and accretion of discount during period	8		0
R&W recovered during period	(27)	[1]	(51)	[1]
Future net R&W benefit at the end of the period	269	[2]	363
U.S. RMBS
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	1,370		1,650
R&W development and accretion of discount during period	157		51
R&W recovered during period	(89)	[1]	(70)	[1]
Future net R&W benefit at the end of the period	$ 1,438	[2]	$ 1,631

[1] Gross amounts recovered were $92 million and $77 million for First Quarter 2013 and 2012, respectively.

[2] Includes excess spread that the Company will receive as salvage as a result of a settlement agreement with an R&W provider.