Subsequent Events (Details) - Subsequent Event [Member] - USD ($)	3 Months Ended
	Mar. 31, 2018	Feb. 12, 2018
Discount on Deferred Amounts Resulting in Adjustment to Loss Reserves		$ 288,000,000
Cancellation of Surplus Notes and Accrued Interest		809,520,000
Debt Modification Criteria, Change in Cash Flows	10.00%
Deferred Payment Obligation [Member]
One Dollar Outstanding		1.00
Cash Payment Amount		0.40
Payment Amount in New Secured Notes		0.41
Payment Amount in Existing Surplus Notes		0.125
Discount Amount		0.065
Ambac [Member] | Deferred Payment Obligation [Member]
One Dollar Outstanding		1.00
Payment Amount in New Secured Notes		0.91
Discount Amount		$ 0.09