Commitments and Contingencies	6 Months Ended
Jun. 30, 2016
Commitments and Contingencies Disclosure [Abstract]
Commitments and Contingencies	Commitments and Contingencies Legal Proceedings Lawsuits arise in the ordinary course of the Company’s business. It is the opinion of the Company’s management, based upon the information available, that the expected outcome of litigation against the Company, individually or in the aggregate, will not have a material adverse effect on the Company’s financial position or liquidity, although an adverse resolution of litigation against the Company in a fiscal quarter or year could have a material adverse effect on the Company’s results of operations in a particular quarter or year. In addition, in the ordinary course of their respective businesses, certain of the Company's subsidiaries assert claims in legal proceedings against third parties to recover losses paid in prior periods or prevent losses in the future. For example, as described in the "Recovery Litigation" section of Note 5, Expected Loss to be Paid, in January 2016, the Company commenced an action for declaratory judgment and injunctive relief in the U.S. District Court for the District of Puerto Rico to invalidate executive orders issued by the Governor of Puerto Rico directing the retention or transfer of certain taxes and revenues pledged to secure the payment of certain bonds insured by the Company. In July 2016, the Company filed a motion and form of complaint in the U.S. District Court for the District of Puerto Rico seeking relief from the PROMESA stay in order to file a complaint to protect its interest in certain pledged PRHTA toll revenues. Also, in December 2008, the Company filed a claim in the Supreme Court of the State of New York against an investment manager in a transaction it insured alleging breach of fiduciary duty, gross negligence and breach of contract. The amounts, if any, the Company will recover in these and other proceedings to recover losses are uncertain, and recoveries, or failure to obtain recoveries, in any one or more of these proceedings during any quarter or year could be material to the Company’s results of operations in that particular quarter or year. The Company establishes accruals for litigation and regulatory matters to the extent it is probable that a loss has been incurred and the amount of that loss can be reasonably estimated. For litigation and regulatory matters where a loss may be reasonably possible, but not probable, or is probable but not reasonably estimable, no accrual is established, but if the matter is material, it is disclosed, including matters discussed below. The Company reviews relevant information with respect to its litigation and regulatory matters on a quarterly, and annual basis and updates its accruals, disclosures and estimates of reasonably possible loss based on such reviews. Litigation Proceedings Relating to the Company’s Financial Guaranty Business The Company receives subpoenas duces tecum and interrogatories from regulators from time to time. On November 28, 2011, Lehman Brothers International (Europe) (in administration) (“LBIE”) sued AGFP, an affiliate of AGC which in the past had provided credit protection to counterparties under credit default swaps. AGC acts as the credit support provider of AGFP under these credit default swaps. LBIE’s complaint, which was filed in the Supreme Court of the State of New York, alleged that AGFP improperly terminated nine credit derivative transactions between LBIE and AGFP and improperly calculated the termination payment in connection with the termination of 28 other credit derivative transactions between LBIE and AGFP. Following defaults by LBIE, AGFP properly terminated the transactions in question in compliance with the agreement between AGFP and LBIE, and calculated the termination payment properly. AGFP calculated that LBIE owes AGFP approximately $29 million in connection with the termination of the credit derivative transactions, whereas LBIE asserted in the complaint that AGFP owes LBIE a termination payment of approximately $1.4 billion. On February 3, 2012, AGFP filed a motion to dismiss certain of the counts in the complaint, and on March 15, 2013, the court granted AGFP's motion to dismiss the count relating to improper termination of the nine credit derivative transactions and denied AGFP's motion to dismiss the counts relating to the remaining transactions. On February 22, 2016, AGFP filed a motion for summary judgment on the remaining causes of action asserted by LBIE and on AGFP's counterclaims. Oral argument on AGFP's motion took place on July 21, 2016. LBIE's administrators disclosed in an April 10, 2015 report to LBIE’s unsecured creditors that LBIE's valuation expert has calculated LBIE's damages in aggregate for the 28 transactions to range between a minimum of approximately $200 million and a maximum of approximately $500 million, depending on what adjustment, if any, is made for AGFP's credit risk and excluding any applicable interest. Notwithstanding the range calculated by LBIE's valuation expert, the Company cannot reasonably estimate the possible loss, if any, that may arise from this lawsuit. On September 25, 2013, Wells Fargo Bank, N.A., as trust administrator of the MASTR Adjustable Rate Mortgages Trust 2007-3, filed an interpleader complaint in the U.S. District Court for the Southern District of New York against AGM, among others, relating to the right of AGM to be reimbursed from certain cashflows for principal claims paid in respect of insured certificates. The Company estimates that an adverse outcome to the interpleader proceeding could increase losses on the transaction by approximately $10 - $20 million, net of expected settlement payments and reinsurance in force. Proceedings Resolved Since December 31, 2015 On May 28, 2014, Houston Casualty Company Europe, Seguros y Reseguros, S.A. (“HCCE”) notified Radian Asset that it was demanding arbitration against Radian Asset in connection with housing cooperative losses presented to Radian Asset by HCCE under several years of quota-share surety reinsurance contracts. Through November 30, 2015, HCCE had presented AGC, as successor to Radian Asset, with approximately €15 million in claims. In January 2016, Assured Guaranty and HCCE settled all the claims related to the Spanish housing cooperative losses. Proceedings Related to AGMH’s Former Financial Products Business The following is a description of legal proceedings involving AGMH’s former Financial Products Business. Although the Company did not acquire AGMH’s former Financial Products Business, which included AGMH’s former GIC business, medium term notes business and portions of the leveraged lease businesses, certain legal proceedings relating to those businesses were against entities that the Company did acquire. While Dexia SA and Dexia Crédit Local S.A. (together, "Dexia") have paid all expenses and settlement amounts due to date as a result of the proceedings described below, such indemnification might not be sufficient to fully hold the Company harmless against any injunctive relief or civil or criminal sanction that is imposed against AGMH or its subsidiaries as a result of any potential newly asserted claims related to these matters. Governmental Investigations into Former Financial Products Business AGMH and/or AGM received subpoenas duces tecum and interrogatories or civil investigative demands from the Attorneys General of the States of Connecticut, Florida, Illinois, Massachusetts, Missouri, New York, Texas and West Virginia relating to their investigations of alleged bid rigging of municipal GICs. In addition, AGMH received a subpoena from the Antitrust Division of the Department of Justice in November 2006 issued in connection with an ongoing criminal investigation of bid rigging of awards of municipal GICs and other municipal derivatives. AGMH responded to such requests when they were received several years ago. While it is possible AGMH may receive additional inquiries from these or other regulators, the Company is not currently aware that any governmental authority, including such Attorneys General or the Department of Justice, are actively pursuing or contemplating legal proceedings with respect to AGMH's former Financial Products Business. Lawsuits Relating to Former Financial Products Business From 2008 through 2010, complaints were brought on behalf of a purported class of state, local and municipal government entities alleging federal antitrust violations in the municipal derivatives industry, seeking damages and alleging, among other things, a conspiracy to fix the pricing of, and manipulate bids for, municipal derivatives, including GICs. These actions were consolidated before one judge in the Southern District of New York as MDL 1950. Following motions to dismiss, amended class action complaints were filed on behalf of a putative class of plaintiffs. The most recently amended, operative class action complaint does not list AGMH or its affiliates as defendants or co-conspirators. On July 8, 2016, the MDL 1950 Court entered an order approving settlement of the remaining class claims, resolving the putative class case. In addition, the Attorney General of the State of West Virginia filed a lawsuit that, as amended, named AGM and Assured Guaranty US Holdings as defendants and alleged a conspiracy to decrease the returns that West Virginia public entities earned on municipal derivative instruments. Also, approximately 19 California and New York government entities brought individual lawsuits that were not a part of the class action and that did not dismiss AGMH or its affiliates. All these cases were transferred to the Southern District of New York and consolidated with MDL 1950 for pretrial purposes. In June and July 2016, Dexia executed settlement agreements covering the action brought by the Attorney General of the State of West Virginia and the actions brought by the individual California and New York plaintiffs, and on July 1, 2016 and July 27, 2016, respectively, the MDL 1950 court dismissed with prejudice the claims against Assured Guaranty US Holdings and AGM in all such actions. Those settlements release all claims as to Assured Guaranty US Holdings, AGMH and AGM, as well as their parents, subsidiaries and affiliates.

Commitments and Contingencies

Legal Proceedings

Lawsuits arise in the ordinary course of the Company’s business. It is the opinion of the Company’s management, based upon the information available, that the expected outcome of litigation against the Company, individually or in the aggregate, will not have a material adverse effect on the Company’s financial position or liquidity, although an adverse resolution of litigation against the Company in a fiscal quarter or year could have a material adverse effect on the Company’s results of operations in a particular quarter or year.

In addition, in the ordinary course of their respective businesses, certain of the Company's subsidiaries assert claims in legal proceedings against third parties to recover losses paid in prior periods or prevent losses in the future. For example, as described in the "Recovery Litigation" section of Note 5, Expected Loss to be Paid, in January 2016, the Company commenced an action for declaratory judgment and injunctive relief in the U.S. District Court for the District of Puerto Rico to invalidate executive orders issued by the Governor of Puerto Rico directing the retention or transfer of certain taxes and revenues pledged to secure the payment of certain bonds insured by the Company. In July 2016, the Company filed a motion and form of complaint in the U.S. District Court for the District of Puerto Rico seeking relief from the PROMESA stay in order to file a complaint to protect its interest in certain pledged PRHTA toll revenues. Also, in December 2008, the Company filed a claim in the Supreme Court of the State of New York against an investment manager in a transaction it insured alleging breach of fiduciary duty, gross negligence and breach of contract. The amounts, if any, the Company will recover in these and other proceedings to recover losses are uncertain, and recoveries, or failure to obtain recoveries, in any one or more of these proceedings during any quarter or year could be material to the Company’s results of operations in that particular quarter or year.

The Company establishes accruals for litigation and regulatory matters to the extent it is probable that a loss has been incurred and the amount of that loss can be reasonably estimated. For litigation and regulatory matters where a loss may be reasonably possible, but not probable, or is probable but not reasonably estimable, no accrual is established, but if the matter is material, it is disclosed, including matters discussed below. The Company reviews relevant information with respect to its litigation and regulatory matters on a quarterly, and annual basis and updates its accruals, disclosures and estimates of reasonably possible loss based on such reviews.

Litigation

Proceedings Relating to the Company’s Financial Guaranty Business

The Company receives subpoenas duces tecum and interrogatories from regulators from time to time.

On November 28, 2011, Lehman Brothers International (Europe) (in administration) (“LBIE”) sued AGFP, an affiliate of AGC which in the past had provided credit protection to counterparties under credit default swaps. AGC acts as the credit support provider of AGFP under these credit default swaps. LBIE’s complaint, which was filed in the Supreme Court of the State of New York, alleged that AGFP improperly terminated nine credit derivative transactions between LBIE and AGFP and improperly calculated the termination payment in connection with the termination of 28 other credit derivative transactions between LBIE and AGFP. Following defaults by LBIE, AGFP properly terminated the transactions in question in compliance with the agreement between AGFP and LBIE, and calculated the termination payment properly. AGFP calculated that LBIE owes AGFP approximately $29 million in connection with the termination of the credit derivative transactions, whereas LBIE asserted in the complaint that AGFP owes LBIE a termination payment of approximately $1.4 billion. On February 3, 2012, AGFP filed a motion to dismiss certain of the counts in the complaint, and on March 15, 2013, the court granted AGFP's motion to dismiss the count relating to improper termination of the nine credit derivative transactions and denied AGFP's motion to dismiss the counts relating to the remaining transactions. On February 22, 2016, AGFP filed a motion for summary judgment on the remaining causes of action asserted by LBIE and on AGFP's counterclaims. Oral argument on AGFP's motion took place on July 21, 2016. LBIE's administrators disclosed in an April 10, 2015 report to LBIE’s unsecured creditors that LBIE's valuation expert has calculated LBIE's damages in aggregate for the 28 transactions to range between a minimum of approximately $200 million and a maximum of approximately $500 million, depending on what adjustment, if any, is made for AGFP's credit risk and excluding any applicable interest. Notwithstanding the range calculated by LBIE's valuation expert, the Company cannot reasonably estimate the possible loss, if any, that may arise from this lawsuit.

On September 25, 2013, Wells Fargo Bank, N.A., as trust administrator of the MASTR Adjustable Rate Mortgages Trust 2007-3, filed an interpleader complaint in the U.S. District Court for the Southern District of New York against AGM, among others, relating to the right of AGM to be reimbursed from certain cashflows for principal claims paid in respect of insured certificates. The Company estimates that an adverse outcome to the interpleader proceeding could increase losses on the transaction by approximately $10 - $20 million, net of expected settlement payments and reinsurance in force.

Proceedings Resolved Since December 31, 2015

On May 28, 2014, Houston Casualty Company Europe, Seguros y Reseguros, S.A. (“HCCE”) notified Radian Asset that it was demanding arbitration against Radian Asset in connection with housing cooperative losses presented to Radian Asset by HCCE under several years of quota-share surety reinsurance contracts. Through November 30, 2015, HCCE had presented AGC, as successor to Radian Asset, with approximately €15 million in claims. In January 2016, Assured Guaranty and HCCE settled all the claims related to the Spanish housing cooperative losses.

Proceedings Related to AGMH’s Former Financial Products Business

The following is a description of legal proceedings involving AGMH’s former Financial Products Business. Although the Company did not acquire AGMH’s former Financial Products Business, which included AGMH’s former GIC business, medium term notes business and portions of the leveraged lease businesses, certain legal proceedings relating to those businesses were against entities that the Company did acquire. While Dexia SA and Dexia Crédit Local S.A. (together, "Dexia") have paid all expenses and settlement amounts due to date as a result of the proceedings described below, such indemnification might not be sufficient to fully hold the Company harmless against any injunctive relief or civil or criminal sanction that is imposed against AGMH or its subsidiaries as a result of any potential newly asserted claims related to these matters.

Governmental Investigations into Former Financial Products Business

AGMH and/or AGM received subpoenas duces tecum and interrogatories or civil investigative demands from the Attorneys General of the States of Connecticut, Florida, Illinois, Massachusetts, Missouri, New York, Texas and West Virginia relating to their investigations of alleged bid rigging of municipal GICs. In addition, AGMH received a subpoena from the Antitrust Division of the Department of Justice in November 2006 issued in connection with an ongoing criminal investigation of bid rigging of awards of municipal GICs and other municipal derivatives. AGMH responded to such requests when they were received several years ago. While it is possible AGMH may receive additional inquiries from these or other regulators, the Company is not currently aware that any governmental authority, including such Attorneys General or the Department of Justice, are actively pursuing or contemplating legal proceedings with respect to AGMH's former Financial Products Business.

Lawsuits Relating to Former Financial Products Business

From 2008 through 2010, complaints were brought on behalf of a purported class of state, local and municipal government entities alleging federal antitrust violations in the municipal derivatives industry, seeking damages and alleging, among other things, a conspiracy to fix the pricing of, and manipulate bids for, municipal derivatives, including GICs. These actions were consolidated before one judge in the Southern District of New York as MDL 1950. Following motions to dismiss, amended class action complaints were filed on behalf of a putative class of plaintiffs. The most recently amended, operative class action complaint does not list AGMH or its affiliates as defendants or co-conspirators. On July 8, 2016, the MDL 1950 Court entered an order approving settlement of the remaining class claims, resolving the putative class case.

In addition, the Attorney General of the State of West Virginia filed a lawsuit that, as amended, named AGM and Assured Guaranty US Holdings as defendants and alleged a conspiracy to decrease the returns that West Virginia public entities earned on municipal derivative instruments. Also, approximately 19 California and New York government entities brought individual lawsuits that were not a part of the class action and that did not dismiss AGMH or its affiliates. All these cases were transferred to the Southern District of New York and consolidated with MDL 1950 for pretrial purposes. In June and July 2016, Dexia executed settlement agreements covering the action brought by the Attorney General of the State of West Virginia and the actions brought by the individual California and New York plaintiffs, and on July 1, 2016 and July 27, 2016, respectively, the MDL 1950 court dismissed with prejudice the claims against Assured Guaranty US Holdings and AGM in all such actions. Those settlements release all claims as to Assured Guaranty US Holdings, AGMH and AGM, as well as their parents, subsidiaries and affiliates.