Expected Losses to be Paid - Breaches of Representations and Warranties (Details) (USD $)	9 Months Ended			3 Months Ended		9 Months Ended				3 Months Ended		9 Months Ended
	Sep. 30, 2014		Dec. 31, 2013	Sep. 30, 2014 Total first lien	Sep. 30, 2013 Total first lien	Sep. 30, 2014 Total first lien	Sep. 30, 2013 Total first lien	Sep. 30, 2014 RMBS		Sep. 30, 2014 Second lien	Sep. 30, 2013 Second lien	Sep. 30, 2014 Second lien	Sep. 30, 2013 Second lien	Sep. 30, 2014 Bank of America Agreement	Sep. 30, 2014 Bank of America Agreement Total first lien	Sep. 30, 2014 Bank of America Agreement Second lien	Sep. 30, 2014 Deutsche Bank Agreement	Sep. 30, 2014 UBS	May 06, 2013 UBS	Sep. 30, 2014 Other	Sep. 30, 2014 Covered Transactions Deutsche Bank Agreement Transaction	Sep. 12, 2014 Covered Transactions Deutsche Bank Agreement Transaction	Oct. 10, 2013 Covered Transactions Deutsche Bank Agreement Transaction	Oct. 07, 2014 Subsequent event Covered Transactions Deutsche Bank Agreement Transaction	Oct. 07, 2014 Subsequent event External credit rating, non investment grade Covered Transactions Deutsche Bank Agreement Transaction
Guarantor Obligations [Line Items]
Agreement amounts projected to be received in the future	$ 296,000,000
Repurchase amounts paid into the relevant RMBS prior to settlement								579,000,000	[1]
Total R&W receipts and losses avoided, gross of reinsurance	3,829,000,000
Estimated benefit from loan repurchases related to breaches of R and W included in net expected loss estimates	578,000,000
R&W recovered during period	284,000,000			163,000,000	96,000,000	272,000,000	577,000,000			3,000,000	59,000,000	22,000,000	192,000,000
Estimated benefit from loan repurchases related to breaches of R and W included in net expected loss estimates in pursuit	294,000,000
Current Net Par Covered	5,229,000,000														963,000,000	1,250,000,000	1,226,000,000	579,000,000		1,211,000,000
Receipts to September 30, 2014 (net of reinsurance)	2,662,000,000														511,000,000	968,000,000	249,000,000	433,000,000		501,000,000
Estimated Future Receipts (net of reinsurance)	284,000,000														163,000,000		73,000,000	8,000,000		40,000,000
Eligible Assets Held in Trust (gross of reinsurance)	826,000,000														581,000,000		135,000,000	110,000,000
Financial guaranty insurance contracts principal amount not covered under agreements	873,000,000
Loss sharing, percentage														80.00%					85.00%
Maximum loss up to which loss sharing, percentage applicable														6,600,000,000
Collateral losses														4,000,000,000
Estimated cumulative collateral losses														5,100,000,000
Loss sharing percentage, first layer																					80.00%
Maximum aggregate collateral losses up to which first layer of loss sharing will be applicable																					319,000,000
Maximum loss up to which second layer of loss sharing, percentage applicable																					600,000,000
Number of transactions terminated																						1	1	2	1
Number of transactions insured																					8
Net par amount outstanding	418,015,000,000		459,107,000,000
Loss sharing percentage, second layer																					85.00%
Minimum losses at which second later of loss sharing percentage becomes applicable																					389,000,000
Benefits already received	$ 2,954,000,000	[2]

[1] These amounts were paid into the relevant RMBS transactions (rather than to the Company as in most settlements) and distributed in accordance with the priority of payments set out in the relevant transaction documents. Because the Company may insure only a portion of the capital structure of a transaction, such payments will not necessarily directly benefit the Company dollar-for-dollar, especially in first lien transactions.

[2] Includes amounts already received plus projected losses avoided based on base case projections at the time of the termination, net of any payments made in connection with the termination.