Business and Basis of Presentation	9 Months Ended
Sep. 30, 2021
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Business and Basis of Presentation	Business and Basis of Presentation Business Assured Guaranty Ltd. (AGL and, together with its subsidiaries, Assured Guaranty or the Company) is a Bermuda-based holding company that provides, through its operating subsidiaries, credit protection products to the United States (U.S.) and international public finance (including infrastructure) and structured finance markets, as well as asset management services. Through its insurance subsidiaries, the Company applies its credit underwriting judgment, risk management skills and capital markets experience primarily to offer financial guaranty insurance that protects holders of debt instruments and other monetary obligations from defaults in scheduled payments. If an obligor defaults on a scheduled payment due on an obligation, including a scheduled principal or interest payment, the Company is required under its unconditional and irrevocable financial guaranty to pay the amount of the shortfall to the holder of the obligation. The Company markets its financial guaranty insurance directly to issuers and underwriters of public finance and structured finance securities as well as to investors in such obligations. The Company guarantees obligations issued principally in the U.S. and the United Kingdom (U.K.), and also guarantees obligations issued in other countries and regions, including Western Europe, Canada and Australia. The Company also provides specialty insurance and reinsurance on transactions with risk profiles similar to those of its structured finance exposures written in financial guaranty form. Through Assured Investment Management LLC (AssuredIM LLC) and its investment management affiliates (together with AssuredIM LLC, AssuredIM), the Company significantly increased its participation in the asset management business with the completion on October 1, 2019, of its acquisition of all of the outstanding equity interests in BlueMountain Capital Management, LLC (BlueMountain, now known as Assured Investment Management LLC) and its associated entities. AssuredIM is a diversified asset manager that serves as investment advisor to collateralized loan obligations (CLOs), opportunity and liquid strategy funds, as well as certain legacy hedge and opportunity funds now subject to an orderly wind-down. AssuredIM has managed structured and public finance, credit and special situation investments since 2003. AssuredIM provides investment advisory services while leveraging a technology-enabled risk platform, which aims to maximize returns for its clients. Basis of Presentation The unaudited interim condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (GAAP). In management’s opinion, all material adjustments necessary for a fair statement of the financial condition, results of operations and cash flows of the Company, including its consolidated variable interest entities (VIEs), are reflected in the periods presented and are of a normal, recurring nature. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates. These unaudited interim condensed consolidated financial statements are as of September 30, 2021 and cover the three-month period ended September 30, 2021 (Third Quarter 2021), the three-month period ended September 30, 2020 (Third Quarter 2020), the nine-month period ended September 30, 2021 (Nine Months 2021) and the nine-month period ended September 30, 2020 (Nine Months 2020). Certain financial information that is normally included in annual financial statements prepared in accordance with GAAP, but is not required for interim reporting purposes, has been condensed or omitted. The year-end condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by GAAP. Certain prior year balances have been reclassified to conform to the current year's presentation. The unaudited interim condensed consolidated financial statements include the accounts of AGL, its direct and indirect subsidiaries, and its consolidated financial guaranty VIEs (FG VIEs) and consolidated investment vehicles (CIVs). See Note 9, Variable Interest Entities. Intercompany accounts and transactions between and among all consolidated entities have been eliminated. These unaudited interim condensed consolidated financial statements should be read in conjunction with the consolidated financial statements included in the Annual Report on Form 10-K for the year ended December 31, 2020, filed with the U.S. Securities and Exchange Commission (SEC). The Company’s principal insurance subsidiaries are: •Assured Guaranty Municipal Corp. (AGM), domiciled in New York; •Assured Guaranty Corp. (AGC), domiciled in Maryland; •Assured Guaranty UK Limited (AGUK), organized in the U.K.; •Assured Guaranty (Europe) SA (AGE), organized in France; •Assured Guaranty Re Ltd. (AG Re), domiciled in Bermuda; and •Assured Guaranty Re Overseas Ltd. (AGRO), domiciled in Bermuda. The Company’s principal asset management subsidiaries are: •Assured Investment Management LLC; •Assured Investment Management (London) LLP; and •Assured Healthcare Partners LLC. Until April 1, 2021, Municipal Assurance Corp. (MAC) was also a principal insurance subsidiary domiciled in New York. On February 24, 2021, the Company received the last regulatory approval required to execute a multi-step transaction to merge MAC with and into AGM, with AGM as the surviving company. As a result, the Company wrote-off the $16 million carrying value of MAC’s insurance licenses in the first quarter of 2021, which was recorded in other operating expenses in the Insurance segment. AGM, AGC and, until its merger with AGM on April 1, 2021, MAC, (collectively, the U.S. Insurance Subsidiaries), jointly own an investment subsidiary, AG Asset Strategies LLC (AGAS), which invests in funds managed by AssuredIM (AssuredIM Funds). The Company’s organizational structure includes various holding companies, two of which - Assured Guaranty US Holdings Inc. (AGUS) and Assured Guaranty Municipal Holdings Inc. (AGMH) (collectively, the U.S. Holding Companies) - have public debt outstanding. Recent Accounting Standards Adopted Simplification of the Accounting for Income Taxes In December 2019, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. The amendments in this ASU simplify the accounting for income taxes by removing certain exceptions and clarifying certain requirements regarding franchise taxes, goodwill, consolidated tax expenses and annual effective tax rate calculations. The ASU was effective for interim and annual periods beginning after December 15, 2020. This ASU did not have an impact on the Company’s consolidated financial statements. Reference Rate Reform In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting. This ASU provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The amendments in this ASU only apply to contracts that reference the London Interbank Offered Rate (LIBOR) or another reference rate that is expected to be discontinued due to reference rate reform. This ASU became effective upon issuance and may be applied prospectively for contract modifications that occur from March 12, 2020 through December 31, 2022 (the Reference Rate Transition Period). In January 2021, the FASB issued ASU 2021-01, Reference Rate Reform (Topic 848): Scope, which clarifies the scope of relief related to ASU 2020-04. This ASU became effective upon issuance and may be applied on a full retrospective basis as of any date from the beginning of an interim period that includes or is subsequent to March 12, 2020, or prospectively for contract modifications made on or before December 31, 2022. The Company adopted the optional relief afforded by these ASUs in Third Quarter 2021 on a prospective basis, and the guidance will be followed until the optional relief terminates on December 31, 2022. The Company has identified insurance contracts, derivatives and other financial instruments that are directly or indirectly influenced by LIBOR, and will be applying the accounting relief as relevant contract modifications are made during the Reference Rate Transition Period. There was no impact to the Company’s condensed consolidated financial statements upon the initial adoption of these ASUs. Recent Accounting Standards Not Yet Adopted Targeted Improvements to the Accounting for Long-Duration Contracts In August 2018, the FASB issued ASU 2018-12, Financial Services - Insurance (Topic 944): Targeted Improvements to the Accounting for Long-Duration Contracts. The amendments in this ASU: •improve the timeliness of recognizing changes in the liability for future policy benefits and modify the rate used to discount future cash flows, •simplify and improve the accounting for certain market-based options or guarantees associated with deposit (or account balance) contracts, •simplify the amortization of deferred acquisition costs (DAC), and •improve the effectiveness of the required disclosures. This ASU does not affect the Company’s financial guaranty insurance contracts, but may affect its accounting for certain specialty (non-financial guaranty) insurance contracts. In November 2020, the FASB deferred the effective date of this ASU to January 1, 2023 with early adoption permitted. If early adoption is elected, there is transition relief allowing for the transition date to be either the beginning of the prior period presented or the beginning of the earliest period presented. If early adoption is not elected, the transition date is required to be the beginning of the earliest period presented. The Company is evaluating when it will adopt this ASU and does not expect this ASU to have a material effect on its consolidated financial statements.

Assured Guaranty Ltd. (AGL and, together with its subsidiaries, Assured Guaranty or the Company) is a Bermuda-based holding company that provides, through its operating subsidiaries, credit protection products to the United States (U.S.) and international public finance (including infrastructure) and structured finance markets, as well as asset management services.

Through its insurance subsidiaries, the Company applies its credit underwriting judgment, risk management skills and capital markets experience primarily to offer financial guaranty insurance that protects holders of debt instruments and other monetary obligations from defaults in scheduled payments. If an obligor defaults on a scheduled payment due on an obligation, including a scheduled principal or interest payment, the Company is required under its unconditional and irrevocable financial guaranty to pay the amount of the shortfall to the holder of the obligation. The Company markets its financial guaranty insurance directly to issuers and underwriters of public finance and structured finance securities as well as to investors in such obligations. The Company guarantees obligations issued principally in the U.S. and the United Kingdom (U.K.), and also guarantees obligations issued in other countries and regions, including Western Europe, Canada and Australia. The Company also provides specialty insurance and reinsurance on transactions with risk profiles similar to those of its structured finance exposures written in financial guaranty form.

Through Assured Investment Management LLC (AssuredIM LLC) and its investment management affiliates (together with AssuredIM LLC, AssuredIM), the Company significantly increased its participation in the asset management business with the completion on October 1, 2019, of its acquisition of all of the outstanding equity interests in BlueMountain Capital Management, LLC (BlueMountain, now known as Assured Investment Management LLC) and its associated entities. AssuredIM is a diversified asset manager that serves as investment advisor to collateralized loan obligations (CLOs), opportunity and liquid strategy funds, as well as certain legacy hedge and opportunity funds now subject to an orderly wind-down. AssuredIM has managed structured and public finance, credit and special situation investments since 2003. AssuredIM provides investment advisory services while leveraging a technology-enabled risk platform, which aims to maximize returns for its clients.

The unaudited interim condensed consolidated financial statements have been prepared in conformity with accounting principles generally accepted in the United States of America (GAAP). In management’s opinion, all material adjustments necessary for a fair statement of the financial condition, results of operations and cash flows of the Company, including its consolidated variable interest entities (VIEs), are reflected in the periods presented and are of a normal, recurring nature. The preparation of financial statements in conformity with GAAP requires management to make estimates and assumptions that affect the reported amounts of assets and liabilities and disclosure of contingent assets and liabilities as of the date of the financial statements and the reported amounts of revenues and expenses during the reporting period. Actual results could differ from those estimates.

These unaudited interim condensed consolidated financial statements are as of September 30, 2021 and cover the three-month period ended September 30, 2021 (Third Quarter 2021), the three-month period ended September 30, 2020 (Third Quarter 2020), the nine-month period ended September 30, 2021 (Nine Months 2021) and the nine-month period ended September 30, 2020 (Nine Months 2020). Certain financial information that is normally included in annual financial statements prepared in accordance with GAAP, but is not required for interim reporting purposes, has been condensed or omitted. The year-end condensed consolidated balance sheet data was derived from audited financial statements, but does not include all disclosures required by GAAP. Certain prior year balances have been reclassified to conform to the current year's presentation.

The unaudited interim condensed consolidated financial statements include the accounts of AGL, its direct and indirect subsidiaries, and its consolidated financial guaranty VIEs (FG VIEs) and consolidated investment vehicles (CIVs). See Note 9, Variable Interest Entities. Intercompany accounts and transactions between and among all consolidated entities have been eliminated.

These unaudited interim condensed consolidated financial statements should be read in conjunction with the consolidated financial statements included in the Annual Report on Form 10-K for the year ended December 31, 2020, filed with the U.S. Securities and Exchange Commission (SEC).

Until April 1, 2021, Municipal Assurance Corp. (MAC) was also a principal insurance subsidiary domiciled in New York. On February 24, 2021, the Company received the last regulatory approval required to execute a multi-step transaction to merge MAC with and into AGM, with AGM as the surviving company. As a result, the Company wrote-off the $16 million carrying value of MAC’s insurance licenses in the first quarter of 2021, which was recorded in other operating expenses in the Insurance segment.

AGM, AGC and, until its merger with AGM on April 1, 2021, MAC, (collectively, the U.S. Insurance Subsidiaries), jointly own an investment subsidiary, AG Asset Strategies LLC (AGAS), which invests in funds managed by AssuredIM (AssuredIM Funds).

The Company’s organizational structure includes various holding companies, two of which - Assured Guaranty US Holdings Inc. (AGUS) and Assured Guaranty Municipal Holdings Inc. (AGMH) (collectively, the U.S. Holding Companies) - have public debt outstanding.

In December 2019, the Financial Accounting Standards Board (FASB) issued Accounting Standards Update (ASU) 2019-12, Income Taxes (Topic 740): Simplifying the Accounting for Income Taxes. The amendments in this ASU simplify the accounting for income taxes by removing certain exceptions and clarifying certain requirements regarding franchise taxes, goodwill, consolidated tax expenses and annual effective tax rate calculations. The ASU was effective for interim and annual periods beginning after December 15, 2020. This ASU did not have an impact on the Company’s consolidated financial statements.

In March 2020, the FASB issued ASU 2020-04, Reference Rate Reform (Topic 848): Facilitation of the Effects of Reference Rate Reform on Financial Reporting. This ASU provides optional expedients and exceptions for applying GAAP to contracts, hedging relationships, and other transactions affected by reference rate reform if certain criteria are met. The amendments in this ASU only apply to contracts that reference the London Interbank Offered Rate (LIBOR) or another reference rate that is expected to be discontinued due to reference rate reform. This ASU became effective upon issuance and may be applied prospectively for contract modifications that occur from March 12, 2020 through December 31, 2022 (the Reference Rate Transition Period).

In January 2021, the FASB issued ASU 2021-01, Reference Rate Reform (Topic 848): Scope, which clarifies the scope of relief related to ASU 2020-04. This ASU became effective upon issuance and may be applied on a full retrospective basis as of any date from the beginning of an interim period that includes or is subsequent to March 12, 2020, or prospectively for contract modifications made on or before December 31, 2022.

The Company adopted the optional relief afforded by these ASUs in Third Quarter 2021 on a prospective basis, and the guidance will be followed until the optional relief terminates on December 31, 2022. The Company has identified insurance contracts, derivatives and other financial instruments that are directly or indirectly influenced by LIBOR, and will be applying

the accounting relief as relevant contract modifications are made during the Reference Rate Transition Period. There was no impact to the Company’s condensed consolidated financial statements upon the initial adoption of these ASUs.

This ASU does not affect the Company’s financial guaranty insurance contracts, but may affect its accounting for certain specialty (non-financial guaranty) insurance contracts. In November 2020, the FASB deferred the effective date of this ASU to January 1, 2023 with early adoption permitted. If early adoption is elected, there is transition relief allowing for the transition date to be either the beginning of the prior period presented or the beginning of the earliest period presented. If early adoption is not elected, the transition date is required to be the beginning of the earliest period presented. The Company is evaluating when it will adopt this ASU and does not expect this ASU to have a material effect on its consolidated financial statements.