Organization	12 Months Ended
Organization	Dec. 31, 2020
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Organization	ORGANIZATION RenaissanceRe Holdings Ltd. (“RenaissanceRe” or the “Company”) was formed under the laws of Bermuda on June 7, 1993. Together with its wholly owned and majority-owned subsidiaries, joint ventures and managed funds, the Company provides property, casualty and specialty reinsurance and certain insurance solutions to its customers. •Renaissance Reinsurance Ltd. (“Renaissance Reinsurance”), a Bermuda-domiciled reinsurance company, is the Company’s principal reinsurance subsidiary and provides property, casualty and specialty reinsurance coverages to insurers and reinsurers on a worldwide basis. •Renaissance Reinsurance U.S. Inc. (“Renaissance Reinsurance U.S.”) is a reinsurance company domiciled in the state of Maryland that provides property, casualty and specialty reinsurance coverages to insurers and reinsurers, primarily in the Americas. •RenaissanceRe Syndicate 1458 (“Syndicate 1458”) is the Company’s Lloyd’s syndicate. RenaissanceRe Corporate Capital (UK) Limited (“RenaissanceRe CCL”), a wholly owned subsidiary of RenaissanceRe, is Syndicate 1458’s sole corporate member. RenaissanceRe Syndicate Management Ltd. (“RSML”), a wholly owned subsidiary of RenaissanceRe, is the managing agent for Syndicate 1458. •On March 22, 2019, the Company’s wholly owned subsidiary, RenaissanceRe Specialty Holdings (UK) Limited (“RenaissanceRe Specialty Holdings”), completed its previously announced purchase of all of the share capital of RenaissanceRe Europe AG (formerly known as Tokio Millennium Re AG), RenaissanceRe (UK) Limited (formerly known as Tokio Millennium Re (UK) Limited) (“RenaissanceRe UK”), and their respective subsidiaries (collectively, “TMR”) pursuant to a Stock Purchase Agreement by and among the Company, Tokio Marine & Nichido Fire Insurance Co. Ltd. (“Tokio”) and, with respect to certain sections only, Tokio Marine Holdings, Inc. entered into on October 30, 2018 (the “TMR Stock Purchase Agreement”) (the “TMR Stock Purchase”). TMR comprised the treaty reinsurance business of Tokio Marine Holdings, Inc. The results of operations of TMR from March 22, 2019, through December 31, 2019, are reflected in the Company’s results of operations for the year ended December 31, 2019. Refer to “Note 3. Acquisition of Tokio Millennium Re” for additional information regarding the TMR Stock Purchase. The Company sold RenaissanceRe UK, a U.K.-domiciled reinsurance company in run-off, to an investment vehicle managed by AXA Liabilities Managers, an affiliate of AXA XL, on August 18, 2020. Refer to “Note 21. Sale of RenaissanceRe UK” for additional information regarding the sale. •RenaissanceRe Europe AG (“RREAG”) , a Swiss-domiciled reinsurance company, which has branches in Australia, Bermuda, the U.K. and the U.S., provides property, casualty and specialty reinsurance coverages to insurers and reinsurers on a worldwide basis. •RenaissanceRe Specialty U.S. Ltd. (“RenaissanceRe Specialty U.S.”), a Bermuda-domiciled insurer, which operates subject to U.S. federal income tax. •DaVinci Reinsurance Ltd. (“DaVinci”), a wholly-owned subsidiary of DaVinciRe Holdings Ltd. (“DaVinciRe”), is a managed joint venture formed by the Company to principally write property catastrophe reinsurance and certain casualty and specialty reinsurance lines of business on a global basis. •Top Layer Reinsurance Ltd. (“Top Layer Re”) is a managed joint venture formed by the Company to write high excess non-U.S. property catastrophe reinsurance. •RenaissanceRe Underwriting Managers U.S. LLC, is licensed as a reinsurance intermediary broker in the State of Connecticut and underwrites specialty treaty reinsurance solutions on both a quota share and excess of loss basis on behalf of affiliates. •Renaissance Underwriting Managers, Ltd. (“RUM”), a wholly owned subsidiary of RenaissanceRe, acts as exclusive underwriting manager for certain of our joint ventures or managed funds in return for fee-based income and profit participation. •RenaissanceRe Fund Management Ltd. (“RFM”) is a wholly-owned Bermuda exempted company and the Company’s fund manager. RFM acts as the exclusive investment fund manager for several of the Company’s joint ventures or managed funds, in return for a management fee, a performance based incentive fee, or both. Fund Manager is registered as an Exempt Reporting Adviser with the SEC and serves as the investment adviser to third-party investors in the various private investment partnerships and insurance-related investment products offered by the Company. •RenaissanceRe Medici Fund Ltd. (“Medici”) is an exempted company, incorporated under the laws of Bermuda and registered as an institutional fund. Medici invests, primarily on behalf of third-party investors, in various instruments that have returns primarily tied to property catastrophe risk. •Upsilon RFO Re Ltd., formerly known as Upsilon Reinsurance II Ltd. (“Upsilon RFO”), a Bermuda domiciled special purpose insurer (“SPI”), is a managed fund formed by the Company principally to provide additional capacity to the worldwide aggregate and per-occurrence primary and retrocessional property catastrophe excess of loss market. •RenaissanceRe Upsilon Fund Ltd., an exempted Bermuda segregated accounts company registered as a Class A Professional Fund provides a fund structure through which third-party investors can invest in reinsurance risk managed by the Company. •Vermeer Reinsurance Ltd. (“Vermeer”), an exempted Bermuda reinsurer, provides capacity focused on risk remote layers in the U.S. property catastrophe market. The Company maintains a majority voting control of Vermeer, while Stichting Pensioenfonds Zorg en Welzijn (“PFZW”), a pension fund represented by PGGM Vermogensbeheer B.V., a Dutch pension fund manager, retains economic benefits. •Fibonacci Reinsurance Ltd. ("Fibonacci Re"), a Bermuda-domiciled SPI, provides collateralized capacity to Renaissance Reinsurance and its affiliates. Fibonacci Re raises capital from third-party investors and the Company, via private placements of participating notes which are listed on the Bermuda Stock Exchange. •The Company and Reinsurance Group of America, Incorporated have engaged in an initiative (“Langhorne”) to source third-party capital to support reinsurers targeting large in-force life and annuity blocks. Langhorne Holdings LLC (“Langhorne Holdings”) was incorporated to own and manage certain reinsurance entities within Langhorne. Langhorne Partners LLC (“Langhorne Partners”) is the general partner for Langhorne and manages the third-parties investing in Langhorne Holdings. •Mona Lisa Re Ltd. (“Mona Lisa Re”), a Bermuda domiciled SPI, provides reinsurance capacity to subsidiaries of RenaissanceRe, namely Renaissance Reinsurance and DaVinci, through reinsurance agreements which are collateralized and funded by Mona Lisa Re through the issuance of one or more series of principal-at-risk variable rate notes. •Following the acquisition of TMR, the Company managed Shima Reinsurance Ltd. (“Shima Re”), Norwood Re Ltd. (“Norwood Re”) and Blizzard Re Ltd. (“Blizzard,” together with Shima Re and Norwood Re, the “TMR managed third-party capital vehicles”), which provided third-party investors with access to reinsurance risk. The TMR managed third-party capital vehicles no longer write new business. The Company ceased providing management services to Blizzard effective November 1, 2020, and Shima Re and Norwood Re effective December 1, 2020.