Subsequent Events	9 Months Ended
Sep. 30, 2018
Subsequent Events [Abstract]
Subsequent Events	SUBSEQUENT EVENTS Acquisition of Tokio Millennium Re On October 30, 2018, the Company announced it had entered into a Stock Purchase Agreement by and among the Company, Tokio Marine & Nichido Fire Insurance Co. Ltd. and, with respect to certain sections only, Tokio Marine Holdings, Inc. (the “TMR Stock Purchase Agreement”), pursuant to which the Company has agreed, subject to the terms and conditions therein, to cause its wholly owned subsidiary RenaissanceRe Specialty Holdings (UK) Limited to purchase all of the share capital of Tokio Millennium Re AG and Tokio Millennium Re (UK) Limited, together with their respective subsidiaries (the “TMR Group Entities”). This transaction is expected to close in the first half of 2019, subject to the closing conditions set forth in the TMR Stock Purchase Agreement, including receipt of required regulatory approvals. State Farm Stock Purchase On October 30, 2018, the Company also announced entry into an Investment Agreement by and between the Company and State Farm Mutual Automobile Insurance Company (“State Farm”), pursuant to which State Farm has agreed, subject to the terms and conditions therein, to purchase 1,947,496 Common Shares of the Company in exchange for $250.0 million in a private placement. This transaction is expected to close in the fourth quarter of 2018, subject to the expiration of the waiting period under the Hart-Scott-Rodino Act. Investment in Catalina Holdings (Bermuda) Ltd (“Catalina”) In January 2018, the Company announced it had signed a definitive agreement to acquire a minority shareholding in Catalina, subject to regulatory approval and other closing conditions. On October 10, 2018, the Company closed on its investment and became a minority shareholder alongside Catalina’s management. Hurricane Michael The Company currently estimates, on a preliminary basis, that losses from Hurricane Michael will have an estimated net negative impact on net income (loss) available (attributable) to RenaissanceRe common shareholders of approximately $100.0 million on its fourth quarter 2018 results of operations. Net negative impact includes the sum of estimates of net claims and claim expenses incurred, earned reinstatement premiums assumed and ceded, lost profit commissions and redeemable noncontrolling interest. The Company’s estimate of Hurricane Michael’s impact on the financial results is based on a review of its potential exposures, preliminary discussions with certain counterparties and catastrophe modeling techniques. Meaningful uncertainty regarding the estimates and the nature and extent of the losses from the Hurricane Michael remains, driven by the magnitude and recent occurrence, relatively limited claims data received to date, the contingent nature of business interruption and other exposures, potential uncertainties relating to reinsurance recoveries and other factors inherent in loss estimation, among other things. Accordingly, the Company’s actual net negative impact from this event may vary from these preliminary estimates, perhaps materially. Updated estimates related to this event will be reflected in RenaissanceRe’s fourth quarter 2018 results of operations, when reported, and changes in these estimates will be recorded in the period in which they occur.

SUBSEQUENT EVENTS

Acquisition of Tokio Millennium Re

On October 30, 2018, the Company announced it had entered into a Stock Purchase Agreement by and among the Company, Tokio Marine & Nichido Fire Insurance Co. Ltd. and, with respect to certain sections only, Tokio Marine Holdings, Inc. (the “TMR Stock Purchase Agreement”), pursuant to which the Company has agreed, subject to the terms and conditions therein, to cause its wholly owned subsidiary RenaissanceRe Specialty Holdings (UK) Limited to purchase all of the share capital of Tokio Millennium Re AG and Tokio Millennium Re (UK) Limited, together with their respective subsidiaries (the “TMR Group Entities”). This transaction is expected to close in the first half of 2019, subject to the closing conditions set forth in the TMR Stock Purchase Agreement, including receipt of required regulatory approvals.

State Farm Stock Purchase

On October 30, 2018, the Company also announced entry into an Investment Agreement by and between the Company and State Farm Mutual Automobile Insurance Company (“State Farm”), pursuant to which State Farm has agreed, subject to the terms and conditions therein, to purchase 1,947,496 Common Shares of the Company in exchange for $250.0 million in a private placement. This transaction is expected to close in the fourth quarter of 2018, subject to the expiration of the waiting period under the Hart-Scott-Rodino Act.

Investment in Catalina Holdings (Bermuda) Ltd (“Catalina”)

In January 2018, the Company announced it had signed a definitive agreement to acquire a minority shareholding in Catalina, subject to regulatory approval and other closing conditions. On October 10, 2018, the Company closed on its investment and became a minority shareholder alongside Catalina’s management.

Hurricane Michael

The Company currently estimates, on a preliminary basis, that losses from Hurricane Michael will have an estimated net negative impact on net income (loss) available (attributable) to RenaissanceRe common shareholders of approximately $100.0 million on its fourth quarter 2018 results of operations.

Net negative impact includes the sum of estimates of net claims and claim expenses incurred, earned reinstatement premiums assumed and ceded, lost profit commissions and redeemable noncontrolling interest. The Company’s estimate of Hurricane Michael’s impact on the financial results is based on a review of its potential exposures, preliminary discussions with certain counterparties and catastrophe modeling techniques.

Meaningful uncertainty regarding the estimates and the nature and extent of the losses from the Hurricane Michael remains, driven by the magnitude and recent occurrence, relatively limited claims data received to date, the contingent nature of business interruption and other exposures, potential uncertainties relating to reinsurance recoveries and other factors inherent in loss estimation, among other things. Accordingly, the Company’s actual net negative impact from this event may vary from these preliminary estimates, perhaps materially. Updated estimates related to this event will be reflected in RenaissanceRe’s fourth quarter 2018 results of operations, when reported, and changes in these estimates will be recorded in the period in which they occur.