Variable Interest Entities	12 Months Ended
Dec. 31, 2017
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Variable Interest Entities	VARIABLE INTEREST ENTITIES Upsilon RFO Effective January 1, 2013, the Company formed and launched Upsilon RFO, a managed joint venture, and a Bermuda domiciled SPI, to provide additional capacity to the worldwide aggregate and per-occurrence retrocessional property catastrophe excess of loss market. The shareholders (other than the Class A shareholder) participate in substantially all of the profits or losses of Upsilon RFO while their shares remain outstanding. The shareholders (other than the Class A shareholder) indemnify Upsilon RFO against losses relating to insurance risk and therefore these shares have been accounted for as prospective reinsurance under FASB ASC Topic Financial Services - Insurance. Upsilon RFO is considered a VIE as it has insufficient equity capital to finance its activities without additional financial support. The Company is the primary beneficiary of Upsilon RFO as it: (i) has the power over the activities that most significantly impact the economic performance of Upsilon RFO and (ii) has the obligation to absorb expected losses and the right to receive expected benefits that could be significant to Upsilon RFO, in accordance with the accounting guidance. As a result, the Company consolidates Upsilon RFO and all significant inter-company transactions have been eliminated. Other than its equity investment in Upsilon RFO, the Company has not provided financial or other support to Upsilon RFO that it was not contractually required to provide. 2016 During 2016, Upsilon RFO returned $242.5 million of capital to its investors, including $59.8 million to the Company. In addition, during 2016, $166.6 million of Upsilon RFO non-voting preference shares were issued to existing investors therein, including $55.2 million to the Company. At December 31, 2016, the Company’s participation in the risks assumed by Upsilon RFO was 28.8%. 2017 During 2017, Upsilon RFO returned $84.3 million of capital to its investors, including $33.0 million to the Company. In addition, during 2017, $180.6 million of Upsilon RFO non-voting preference shares were issued to existing investors therein, including $27.2 million to the Company, and an existing third-party investor purchased $7.5 million of Upsilon RFO non-voting preference shares from the Company. At December 31, 2017, the Company’s participation in the risks assumed by Upsilon RFO was 20.8%. At December 31, 2017, the Company’s consolidated balance sheet included total assets and total liabilities of Upsilon RFO of $1.2 billion and $1.2 billion, respectively (2016 - $193.0 million and $193.0 million, respectively). See “Note 23. Subsequent Events” for additional information related to Upsilon RFO’s non-voting preference shares subsequent to December 31, 2017. Mona Lisa Re Ltd. (“Mona Lisa Re”) On March 14, 2013, Mona Lisa Re was licensed as a Bermuda domiciled SPI to provide reinsurance capacity to subsidiaries of RenaissanceRe, namely Renaissance Reinsurance and DaVinci, through reinsurance agreements which will be collateralized and funded by Mona Lisa Re through the issuance of one or more series of principal-at-risk variable rate notes to third-party investors. Upon issuance of a series of notes by Mona Lisa Re, all of the proceeds from the issuance were deposited into collateral accounts, separated by series, to fund any potential obligation under the reinsurance agreements entered into with Renaissance Reinsurance and/or DaVinci underlying such series of notes. The outstanding principal amount of each series of notes generally will be returned to holders of such notes upon the expiration of the risk period underlying such notes, unless an event occurs which causes a loss under the applicable series of notes, in which case the amount returned will be reduced by such noteholder’s pro rata share of such loss, as specified in the applicable governing documents of such notes. In addition, holders of such notes are generally entitled to interest payments, payable quarterly, as determined by the applicable governing documents of each series of notes. The Company concluded that Mona Lisa Re meets the definition of a VIE as it does not have sufficient equity capital to finance its activities. The Company evaluated its relationship with Mona Lisa Re and concluded it does not have a variable interest in Mona Lisa Re. As a result, the financial position and results of operations of Mona Lisa Re are not consolidated by the Company. The Company has not provided financial or other support to Mona Lisa Re that it was not contractually required to provide. At December 31, 2017, the total assets and total liabilities of Mona Lisa Re were $25.9 million and $25.9 million, respectively (2016 - $184.2 million and $184.2 million, respectively). The only transactions related to Mona Lisa Re that are recorded in the Company’s consolidated financial statements are the ceded reinsurance agreements entered into by Renaissance Reinsurance and DaVinci which are accounted for as prospective reinsurance under FASB ASC Topic Financial Services - Insurance. Renaissance Reinsurance and DaVinci have together entered into ceded reinsurance contracts with Mona Lisa Re with gross premiums ceded of $0.4 million and $0.4 million, respectively, during 2017 (2016 - $7.4 million and $5.1 million, respectively). In addition, Renaissance Reinsurance and DaVinci recognized ceded premiums earned related to the ceded reinsurance contracts with Mona Lisa Re of $4.1 million and $2.9 million, respectively, during 2017 (2016 - $7.3 million and $5.0 million, respectively). Fibonacci Re Effective November 7, 2016, Fibonacci Re, a Bermuda-domiciled SPI, was formed to provide collateralized capacity to Renaissance Reinsurance and its affiliates. Upon issuance of a series of notes by Fibonacci Re, all of the proceeds from the issuance are deposited into collateral accounts, separated by series, to fund any potential obligation under the reinsurance agreements entered into with Renaissance Reinsurance underlying such series of notes. The outstanding principal amount of each series of notes generally is expected to be returned to holders of such notes upon the expiration of the risk period underlying such notes, unless an event occurs which causes a loss under the applicable series of notes, in which case the amount returned is expected to be reduced by such noteholder’s pro rata share of such loss, as specified in the applicable governing documents of such notes. In addition, holders of such notes are generally entitled to interest payments, payable quarterly, as determined by the applicable governing documents of each series of notes. RUM receives an origination and structuring fee in connection with the formation and operation of Fibonacci Re. The Company concluded that Fibonacci Re meets the definition of a VIE as it does not have sufficient equity capital to finance its activities. The Company evaluated its relationship with Fibonacci Re and concluded it is not the primary beneficiary of Fibonacci Re as it does not have power over the activities that most significantly impact the economic performance of Fibonacci Re. As a result, the Company does not consolidate the financial position or results of operations of Fibonacci Re. The only transactions related to Fibonacci Re that will be recorded in the Company’s consolidated financial statements will be the ceded reinsurance agreements entered into by Renaissance Reinsurance that are accounted for as prospective reinsurance under FASB ASC Topic Financial Services - Insurance, and the fair value of the participating notes owned by the Company. Other than its investment in the participating notes of Fibonacci Re, the Company has not provided financial or other support to Fibonacci Re that it was not contractually required to provide. The fair value of the Company’s investment in the participating notes of Fibonacci Re is included in other investments. Net of third-party investors, the fair value of the Company’s investment in Fibonacci Re was $14.1 million at December 31, 2017. Renaissance Reinsurance entered into ceded reinsurance contracts with Fibonacci Re with premiums ceded of $9.0 million during 2017. In addition, Renaissance Reinsurance recognized ceded premiums earned related to the ceded reinsurance contracts with Fibonacci Re of $8.2 million during 2017. Langhorne Effective December 22, 2017, the Company and Reinsurance Group of America, Incorporated closed Langhorne, an initiative to source third party capital to support reinsurers targeting large in-force life and annuity blocks. In connection with Langhorne, as of December 31, 2017 the Company has invested $0.6 million in Langhorne Holdings, a company that owns and manages certain reinsurance entities within Langhorne. In addition, the Company has committed to investing in Langhorne Partners, the general partner for Langhorne and the entity which manages the third-party investors investing into Langhorne Holdings. The Company concluded that Langhorne Holdings meets the definition of a VIE as the voting rights are not proportional with the obligations to absorb losses and rights to receive residual returns. The Company evaluated its relationship with Langhorne Holdings and concluded it is not the primary beneficiary of Langhorne Holdings, as it does not have power over the activities that most significantly impact the economic performance of Langhorne Holdings. As a result, the Company does not consolidate the financial position or results of operations of Langhorne Holdings. The Company separately evaluated Langhorne Partners and concluded that it was not a VIE. The Company will account for its investments in Langhorne Holdings and Langhorne Partners under the equity method of accounting, one quarter in arrears. The Company anticipates that its investment in Langhorne will increase, perhaps materially, as in-force life and annuity blocks of businesses are written. Other than its current and committed future equity investment in Langhorne, the Company has not provided financial or other support to Langhorne that it was not contractually required to provide.

VARIABLE INTEREST ENTITIES

Upsilon RFO

Effective January 1, 2013, the Company formed and launched Upsilon RFO, a managed joint venture, and a Bermuda domiciled SPI, to provide additional capacity to the worldwide aggregate and per-occurrence retrocessional property catastrophe excess of loss market.

The shareholders (other than the Class A shareholder) participate in substantially all of the profits or losses of Upsilon RFO while their shares remain outstanding. The shareholders (other than the Class A shareholder) indemnify Upsilon RFO against losses relating to insurance risk and therefore these shares have been accounted for as prospective reinsurance under FASB ASC Topic Financial Services - Insurance.

Upsilon RFO is considered a VIE as it has insufficient equity capital to finance its activities without additional financial support. The Company is the primary beneficiary of Upsilon RFO as it: (i) has the power over the activities that most significantly impact the economic performance of Upsilon RFO and (ii) has the obligation to absorb expected losses and the right to receive expected benefits that could be significant to Upsilon RFO, in accordance with the accounting guidance. As a result, the Company consolidates Upsilon RFO and all significant inter-company transactions have been eliminated. Other than its equity investment in Upsilon RFO, the Company has not provided financial or other support to Upsilon RFO that it was not contractually required to provide.

2016

During 2016, Upsilon RFO returned $242.5 million of capital to its investors, including $59.8 million to the Company. In addition, during 2016, $166.6 million of Upsilon RFO non-voting preference shares were issued to existing investors therein, including $55.2 million to the Company. At December 31, 2016, the Company’s participation in the risks assumed by Upsilon RFO was 28.8%.

2017

During 2017, Upsilon RFO returned $84.3 million of capital to its investors, including $33.0 million to the Company. In addition, during 2017, $180.6 million of Upsilon RFO non-voting preference shares were issued to existing investors therein, including $27.2 million to the Company, and an existing third-party investor purchased $7.5 million of Upsilon RFO non-voting preference shares from the Company. At December 31, 2017, the Company’s participation in the risks assumed by Upsilon RFO was 20.8%.

At December 31, 2017, the Company’s consolidated balance sheet included total assets and total liabilities of Upsilon RFO of $1.2 billion and $1.2 billion, respectively (2016 - $193.0 million and $193.0 million, respectively). See “Note 23. Subsequent Events” for additional information related to Upsilon RFO’s non-voting preference shares subsequent to December 31, 2017.

Mona Lisa Re Ltd. (“Mona Lisa Re”)

On March 14, 2013, Mona Lisa Re was licensed as a Bermuda domiciled SPI to provide reinsurance capacity to subsidiaries of RenaissanceRe, namely Renaissance Reinsurance and DaVinci, through reinsurance agreements which will be collateralized and funded by Mona Lisa Re through the issuance of one or more series of principal-at-risk variable rate notes to third-party investors.

Upon issuance of a series of notes by Mona Lisa Re, all of the proceeds from the issuance were deposited into collateral accounts, separated by series, to fund any potential obligation under the reinsurance agreements entered into with Renaissance Reinsurance and/or DaVinci underlying such series of notes. The outstanding principal amount of each series of notes generally will be returned to holders of such notes upon the expiration of the risk period underlying such notes, unless an event occurs which causes a loss under the applicable series of notes, in which case the amount returned will be reduced by such noteholder’s pro rata share of such loss, as specified in the applicable governing documents of such notes. In addition, holders of such notes are generally entitled to interest payments, payable quarterly, as determined by the applicable governing documents of each series of notes.

The Company concluded that Mona Lisa Re meets the definition of a VIE as it does not have sufficient equity capital to finance its activities. The Company evaluated its relationship with Mona Lisa Re and concluded it does not have a variable interest in Mona Lisa Re. As a result, the financial position and results of operations of Mona Lisa Re are not consolidated by the Company. The Company has not provided financial or other support to Mona Lisa Re that it was not contractually required to provide.

At December 31, 2017, the total assets and total liabilities of Mona Lisa Re were $25.9 million and $25.9 million, respectively (2016 - $184.2 million and $184.2 million, respectively).

The only transactions related to Mona Lisa Re that are recorded in the Company’s consolidated financial statements are the ceded reinsurance agreements entered into by Renaissance Reinsurance and DaVinci which are accounted for as prospective reinsurance under FASB ASC Topic Financial Services - Insurance. Renaissance Reinsurance and DaVinci have together entered into ceded reinsurance contracts with Mona Lisa Re with gross premiums ceded of $0.4 million and $0.4 million, respectively, during 2017 (2016 - $7.4 million and $5.1 million, respectively). In addition, Renaissance Reinsurance and DaVinci recognized ceded premiums earned related to the ceded reinsurance contracts with Mona Lisa Re of $4.1 million and $2.9 million, respectively, during 2017 (2016 - $7.3 million and $5.0 million, respectively).

Fibonacci Re

Effective November 7, 2016, Fibonacci Re, a Bermuda-domiciled SPI, was formed to provide collateralized capacity to Renaissance Reinsurance and its affiliates.

Upon issuance of a series of notes by Fibonacci Re, all of the proceeds from the issuance are deposited into collateral accounts, separated by series, to fund any potential obligation under the reinsurance agreements entered into with Renaissance Reinsurance underlying such series of notes. The outstanding principal amount of each series of notes generally is expected to be returned to holders of such notes upon the expiration of the risk period underlying such notes, unless an event occurs which causes a loss under the applicable series of notes, in which case the amount returned is expected to be reduced by such noteholder’s pro rata share of such loss, as specified in the applicable governing documents of such notes. In addition, holders of such notes are generally entitled to interest payments, payable quarterly, as determined by the applicable governing documents of each series of notes. RUM receives an origination and structuring fee in connection with the formation and operation of Fibonacci Re.

The Company concluded that Fibonacci Re meets the definition of a VIE as it does not have sufficient equity capital to finance its activities. The Company evaluated its relationship with Fibonacci Re and concluded it is not the primary beneficiary of Fibonacci Re as it does not have power over the activities that most significantly impact the economic performance of Fibonacci Re. As a result, the Company does not consolidate the financial position or results of operations of Fibonacci Re.

The only transactions related to Fibonacci Re that will be recorded in the Company’s consolidated financial statements will be the ceded reinsurance agreements entered into by Renaissance Reinsurance that are accounted for as prospective reinsurance under FASB ASC Topic Financial Services - Insurance, and the fair value of the participating notes owned by the Company. Other than its investment in the participating notes of Fibonacci Re, the Company has not provided financial or other support to Fibonacci Re that it was not contractually required to provide.

The fair value of the Company’s investment in the participating notes of Fibonacci Re is included in other investments. Net of third-party investors, the fair value of the Company’s investment in Fibonacci Re was $14.1 million at December 31, 2017.

Renaissance Reinsurance entered into ceded reinsurance contracts with Fibonacci Re with premiums ceded of $9.0 million during 2017. In addition, Renaissance Reinsurance recognized ceded premiums earned related to the ceded reinsurance contracts with Fibonacci Re of $8.2 million during 2017.

Langhorne

Effective December 22, 2017, the Company and Reinsurance Group of America, Incorporated closed Langhorne, an initiative to source third party capital to support reinsurers targeting large in-force life and annuity blocks. In connection with Langhorne, as of December 31, 2017 the Company has invested $0.6 million in Langhorne Holdings, a company that owns and manages certain reinsurance entities within Langhorne. In addition, the Company has committed to investing in Langhorne Partners, the general partner for Langhorne and the entity which manages the third-party investors investing into Langhorne Holdings.

The Company concluded that Langhorne Holdings meets the definition of a VIE as the voting rights are not proportional with the obligations to absorb losses and rights to receive residual returns. The Company evaluated its relationship with Langhorne Holdings and concluded it is not the primary beneficiary of Langhorne Holdings, as it does not have power over the activities that most significantly impact the economic performance of Langhorne Holdings. As a result, the Company does not consolidate the financial position or results of operations of Langhorne Holdings. The Company separately evaluated Langhorne Partners and concluded that it was not a VIE. The Company will account for its investments in Langhorne Holdings and Langhorne Partners under the equity method of accounting, one quarter in arrears.

The Company anticipates that its investment in Langhorne will increase, perhaps materially, as in-force life and annuity blocks of businesses are written. Other than its current and committed future equity investment in Langhorne, the Company has not provided financial or other support to Langhorne that it was not contractually required to provide.