Slicers (applies to each fact value in each table cell)

Reporting Entity [Axis]

0000874501 (http://www.sec.gov/CIK)

Income Tax Disclosure [Abstract]	Period [Axis]
	2016-01-01 - 2016-12-31
Income Tax Disclosure [Abstract]
Major Jurisdictions	The following are the major jurisdictions in which Ambac and its affiliates operate and the earliest tax years subject to examination: Jurisdiction Tax Year United States 2010 New York State 2012 New York City 2012 United Kingdom 2012 Italy 2011
Significant Portions of Deferred Tax Liabilities and Deferred Tax Assets	The tax effects of temporary differences that give rise to significant portions of the deferred tax liabilities and deferred tax assets at December 31, 2016 and 2015 are presented below: December 31, 2016   2015 Deferred tax liabilities:       Insurance intangible $ 336,728   $ 424,239 Variable interest entities 46,343   10,053 Investments 38,656   66,278 Unearned premiums and credit fees 68,682   98,945 Unremitted foreign earnings 30,699   — Other 4,276   34,025 Total deferred tax liabilities 525,384   633,540 Deferred tax assets:       Net operating loss and capital carryforward 1,409,565   1,504,569 Loss reserves 224,553   122,635 AMT Credits 31,532   27,252 Other 16,726   12,752 Sub total deferred tax assets 1,682,376   1,667,208 Valuation allowance 1,158,712   1,035,873 Total deferred tax assets 523,664   631,335 Net deferred tax asset (liability) $ (1,720 )   $ (2,205 )
Schedule of Income before Income Tax, Domestic and Foreign [Table Text Block]	U.S. and foreign components of pre-tax income were as follows: Year Ended December 31, 2016   2015   2014 U.S. $ 77,161   $ 337,753   $ 444,653 Foreign 27,865   172,305   48,600 Total $ 105,026   $ 510,058   $ 493,253
Schedule of Components of Income Tax Expense (Benefit)	The components of the provision for income taxes were as follows: Year Ended December 31, 2016   2015   2014 Current taxes           U. S. federal $ 3,934   $ 16,893   $ 6,085 U.S. state and local 707   182   — Foreign 26,088   2   3,378 Current taxes 30,729   17,077   9,463 Deferred taxes           Deferred taxes (20 )   287   94 Provision for income taxes $ 30,709   $ 17,364   $ 9,557
Schedule Of Income Taxes Charged Credited Directly To Equity	The total effect of income taxes on net income and stockholders’ equity for the years ended December 31, 2016, 2015 and 2014 is as follows: Year Ended December 31, 2016   2015   2014 Total income taxes charged to net income $ 30,709   $ 17,364   $ 9,557 Income taxes charged (credited) to stockholders’ equity:           Unrealized gains (losses) on investment securities 41,602   (55,906 )   88,411 Unrealized gains (losses) on foreign currency translations (58,527 )   (15,628 )   (15,108 ) Change in retirement benefits 3,278   (240 )   (285 ) Valuation allowance to equity 13,647   71,774   (73,018 ) Total effect of income taxes $ 30,709   $ 17,364   $ 9,557
Schedule of Effective Income Tax Rate Reconciliation	The tax provisions in the accompanying Consolidated Statements of Total Comprehensive Loss reflect effective tax rates differing from prevailing Federal corporate income tax rates. The following is a reconciliation of these differences:   2016   2015   2014 Year Ended December 31, Amount   %   Amount   %   Amount   % Tax on income from continuing operations at statutory rate $ 36,759   35.0  %   $ 178,521   35.0  %   $ 172,639   35.0  % Changes in expected tax resulting from:                       Tax-exempt interest (1,561 )   (1.5 )%   (1,454 )   (0.3 )%   (6,811 )   (1.4 )% Goodwill impairment —   —  %   180,079   35.3  %   —   —  % Foreign taxes 26,183   24.9  %   288   0.1  %   3,472   0.7  % Deferred tax substantiation adjustment (171,687 )   (163.5 )%   —   —  %   —   —  % Valuation allowance 139,584   132.9  %   (340,133 )   (66.7 )%   (159,661 )   (32.4 )% Other, net 1,431   1.4  %   63   —  %   (82 )   —  % Tax expense on income from continuing operations $ 30,709   29.2  %   $ 17,364   3.4  %   $ 9,557   1.9  %
Schedule of Unrecognized Tax Benefits Roll Forward	A reconciliation of the beginning and ending amount of unrecognized tax benefits for 2016, 2015 and 2014is as follows: Year Ended December 31, 2016   2015   2014 Balance, beginning of period $ —   $ —   $ — Increases related to prior year tax positions —   —   — Decreases related to prior year tax positions —   —   — Balance, end of period $ —   $ —   $ —
Schedule of Net Operating Loss And Tax Credit Carryovers	Pursuant to the Amended TSA, to the extent Ambac Assurance generates taxable income after September 30, 2011, which is offset with "Allocated NOLs" of $3,650,000, it is obligated to make payments (“Tolling Payments”), subject to certain credits, to Ambac in accordance with the following NOL usage table, where the “Applicable Percentage” is applied to the aggregate amount of federal income tax liability that would have been paid if the Allocated NOLs were not available. NOL Usage Table NOL Usage Tier Allocated NOLs(1)   Applicable Percentage A The first $479,000   15% B The next $1,057,000 after Tier A 40% C The next $1,057,000 after Tier B 10% D The next $1,057,000 after Tier C 15% (1) Bankruptcy-related credits offset the first $5 million payment due under each of the NOL usage Tiers A, B and C. Pursuant to the Internal Revenue Service closing agreement the United States Department of Treasury receives 12.5% of Tier C and 17.5% of Tier D Tolling Payments.