Acquisitions	3 Months Ended
Mar. 31, 2018
Business Combinations [Abstract]
Acquisitions	Acquisitions AGC completed its acquisition of MBIA UK Insurance Limited (MBIA UK), the U.K. operating subsidiary of MBIA Insurance Corporation (MBIA) (the MBIA UK Acquisition) on January 10, 2017 (the MBIA UK Acquisition Date). As consideration for the outstanding shares of MBIA UK plus $23 million in cash, AGC exchanged all its holdings of notes issued in the Zohar II 2005-1 transaction (Zohar II Notes), which were insured by MBIA. AGC’s Zohar II Notes had total outstanding principal of approximately $347 million and fair value of $334 million as of the MBIA UK Acquisition Date. The MBIA UK Acquisition added approximately $12 billion of net par insured on January 10, 2017. In connection with the MBIA UK Acquisition in First Quarter 2017, the Company recognized a $56 million bargain purchase gain and a $2 million gain on settlement of pre-existing relationships. MBIA UK was renamed Assured Guaranty (London) Ltd. and on June 1, 2017, was re-registered as a public limited company (plc). Further, as part of a multi-step transaction, which ultimately is expected to result in AGUK, AGLN and CIFGE transferring their insurance portfolios to and merging with and into AGE, AGLN was sold by AGC to AGM and then contributed by AGM to AGE on June 26, 2017. See Note 1, Business and Basis of Presentation for additional information on the Company's European subsidiaries combination. For additional information on the acquisition of MBIA UK, including the purchase price and the allocation of the purchase price to net assets acquired and the resulting bargain purchase gain and the gain on settlement of pre-existing relationships, see Note 2, Acquisitions, in Part II, Item 8. “Financial Statements and Supplementary Data” of AGL’s Annual Report on Form 10-K for the year ended December 31, 2017.

Acquisitions

AGC completed its acquisition of MBIA UK Insurance Limited (MBIA UK), the U.K. operating subsidiary of MBIA Insurance Corporation (MBIA) (the MBIA UK Acquisition) on January 10, 2017 (the MBIA UK Acquisition Date). As consideration for the outstanding shares of MBIA UK plus $23 million in cash, AGC exchanged all its holdings of notes issued in the Zohar II 2005-1 transaction (Zohar II Notes), which were insured by MBIA. AGC’s Zohar II Notes had total outstanding principal of approximately $347 million and fair value of $334 million as of the MBIA UK Acquisition Date. The MBIA UK Acquisition added approximately $12 billion of net par insured on January 10, 2017. In connection with the MBIA UK Acquisition in First Quarter 2017, the Company recognized a $56 million bargain purchase gain and a $2 million gain on settlement of pre-existing relationships.

MBIA UK was renamed Assured Guaranty (London) Ltd. and on June 1, 2017, was re-registered as a public limited company (plc). Further, as part of a multi-step transaction, which ultimately is expected to result in AGUK, AGLN and CIFGE transferring their insurance portfolios to and merging with and into AGE, AGLN was sold by AGC to AGM and then contributed by AGM to AGE on June 26, 2017. See Note 1, Business and Basis of Presentation for additional information on the Company's European subsidiaries combination.

For additional information on the acquisition of MBIA UK, including the purchase price and the allocation of the purchase price to net assets acquired and the resulting bargain purchase gain and the gain on settlement of pre-existing relationships, see Note 2, Acquisitions, in Part II, Item 8. “Financial Statements and Supplementary Data” of AGL’s Annual Report on Form 10-K for the year ended December 31, 2017.