Subsequent Events	3 Months Ended
Mar. 31, 2018
Subsequent Events [Abstract]
Subsequent Events	Subsequent Events On April 19, 2018, Kendall Re Limited (“Kendall Re”), a Bermuda exempted company was licensed and registered as a special purpose insurer under the Bermuda Insurance Act 1978 and related regulations, as amended. On April 25, 2018, Kendall Re issued $225.0 million Series 2018-1 Class A Principal At-Risk Variable Rate Notes due May 6, 2021 under a variable rate note program from which the proceeds will be used to provide Aspen Bermuda Limited with fully-collateralized retrocessional reinsurance protections against losses from a range of international perils, including U.S. named storm risks, U.S. and Canada earthquake risks, U.S. severe thunderstorms, U.S. wildfires, U.S. winter storms and European windstorms. The results and balance sheet of Kendall Re will not be included within the condensed consolidated financial statements of the Company because the Company holds no variable or voting interest in Kendall Re. On April 20, 2018, Aspen Insurance UK Services Limited, Aspen Insurance U.S. Services, Inc. and Aspen Bermuda Limited entered into an Outsourcing Agreement (the “Agreement”) with Genpact International, Inc., a company incorporated in Delaware, United States (“Genpact”). Pursuant to the Agreement, Genpact will provide Aspen Insurance Holdings Limited and its subsidiaries (collectively, “Aspen”) a range of operational business processes, primarily from their offshore service center in Gurgaon, India, to enable Aspen to deliver greater operating effectiveness and efficiencies. The Agreement has minimum service levels that Genpact must meet or exceed. Genpact will progressively assume responsibility for these services during a phased transition period that will extend over 12-15 months in line with a transition plan. The Agreement is effective April 1, 2018 and has an initial term period of five years. Aspen has the right to extend the Agreement for three additional one year terms. None of Aspen’s employees will become employees of Genpact. On December 20, 2017, the Company committed $100.0 million as a limited partner to a real estate fund. On May 10, 2018, the Company received an initial capital call of $86.2 million in the real estate fund. For more information, please refer to Note 16 “Commitments and Contingencies” in this report.

Subsequent Events

On April 19, 2018, Kendall Re Limited (“Kendall Re”), a Bermuda exempted company was licensed and registered as a special purpose insurer under the Bermuda Insurance Act 1978 and related regulations, as amended. On April 25, 2018, Kendall Re issued $225.0 million Series 2018-1 Class A Principal At-Risk Variable Rate Notes due May 6, 2021 under a variable rate note program from which the proceeds will be used to provide Aspen Bermuda Limited with fully-collateralized retrocessional reinsurance protections against losses from a range of international perils, including U.S. named storm risks, U.S. and Canada earthquake risks, U.S. severe thunderstorms, U.S. wildfires, U.S. winter storms and European windstorms. The results and balance sheet of Kendall Re will not be included within the condensed consolidated financial statements of the Company because the Company holds no variable or voting interest in Kendall Re.

On April 20, 2018, Aspen Insurance UK Services Limited, Aspen Insurance U.S. Services, Inc. and Aspen Bermuda Limited entered into an Outsourcing Agreement (the “Agreement”) with Genpact International, Inc., a company incorporated in Delaware, United States (“Genpact”). Pursuant to the Agreement, Genpact will provide Aspen Insurance Holdings Limited and its subsidiaries (collectively, “Aspen”) a range of operational business processes, primarily from their offshore service center in Gurgaon, India, to enable Aspen to deliver greater operating effectiveness and efficiencies. The Agreement has minimum service levels that Genpact must meet or exceed. Genpact will progressively assume responsibility for these services during a phased transition period that will extend over 12-15 months in line with a transition plan. The Agreement is effective April 1, 2018 and has an initial term period of five years. Aspen has the right to extend the Agreement for three additional one year terms. None of Aspen’s employees will become employees of Genpact.

On December 20, 2017, the Company committed $100.0 million as a limited partner to a real estate fund. On May 10, 2018, the Company received an initial capital call of $86.2 million in the real estate fund. For more information, please refer to Note 16 “Commitments and Contingencies” in this report.