v2.4.0.6

Fair Value Measurements (Narrative) (Details) (USD $) | 3 Months Ended |  | 3 Months Ended | 0 Months Ended |  |  | 0 Months Ended |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 3 Months Ended |  |  |  |  |  |  |
--- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | ---
Mar. 31, 2012 | Mar. 31, 2011 | Dec. 31, 2011 | Mar. 31, 2012 Other Investments [Member] Investment Income, Net [Member] | Mar. 31, 2011 Other Investments [Member] Investment Income, Net [Member] | Mar. 31, 2012 Other Assets and Liabilities [Member] Other (Loss) Income [Member] | Mar. 31, 2011 Other Assets and Liabilities [Member] Other (Loss) Income [Member] | Jan. 03, 2003 5.875% Senior Notes Due February 15, 2013 [Member] | Mar. 31, 2012 5.875% Senior Notes Due February 15, 2013 [Member] | Dec. 31, 2011 5.875% Senior Notes Due February 15, 2013 [Member] | Mar. 17, 2010 5.75% Senior Notes Due March 15, 2020 [Member] RenRe North America Holdings Inc. [Member] | Mar. 31, 2012 5.75% Senior Notes Due March 15, 2020 [Member] RenRe North America Holdings Inc. [Member] | Dec. 31, 2011 5.75% Senior Notes Due March 15, 2020 [Member] RenRe North America Holdings Inc. [Member] | Mar. 31, 2012 U.S. treasuries [Member] | Dec. 31, 2011 U.S. treasuries [Member] | Mar. 31, 2012 Agencies [Member] | Dec. 31, 2011 Agencies [Member] | Mar. 31, 2012 Non-U.S. government (Sovereign Debt) [Member] | Dec. 31, 2011 Non-U.S. government (Sovereign Debt) [Member] | Mar. 31, 2012 FDIC guaranteed corporate [Member] | Dec. 31, 2011 FDIC guaranteed corporate [Member] | Mar. 31, 2012 Non-U.S. government-backed corporate [Member] | Dec. 31, 2011 Non-U.S. government-backed corporate [Member] | Mar. 31, 2012 Corporate [Member] | Dec. 31, 2011 Corporate [Member] | Mar. 31, 2012 Agency mortgage-backed [Member] years | Dec. 31, 2011 Agency mortgage-backed [Member] years | Mar. 31, 2012 Non-agency prime residential mortgage-backed [Member] years | Dec. 31, 2011 Non-agency prime residential mortgage-backed [Member] years | Mar. 31, 2012 AltA non-agency mortgage-backed [Member] years | Dec. 31, 2011 AltA non-agency mortgage-backed [Member] years | Mar. 31, 2012 Commercial mortgage-backed [Member] years | Dec. 31, 2011 Commercial mortgage-backed [Member] years | Mar. 31, 2012 Asset-backed [Member] years | Dec. 31, 2011 Asset-backed [Member] years | Mar. 31, 2012 Private equity partnerships [Member] | Mar. 31, 2012 Senior secured bank loan funds [Member] | Mar. 31, 2012 Non-U.S. fixed income funds [Member] | Mar. 31, 2012 Hedge funds [Member] | Mar. 31, 2012 Other [Member] | Dec. 31, 2011 Other [Member] | Mar. 31, 2012 Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Dec. 31, 2011 Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] | Mar. 31, 2012 Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] Other [Member] | Dec. 31, 2011 Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] Other [Member] | Mar. 31, 2012 Quoted Prices In Active Markets For Identical Assets (Level 1) [Member] Cash Settled Restricted Stock Unit [Member]
Weighted average effective yield |  |  |  |  |  |  |  |  |  |  |  |  |  | 0.60% | 0.60% | 0.70% | 0.50% | 2.90% | 2.30% | 0.20% | 0.30% | 1.30% | 1.40% | 3.70% | 4.20% | 1.40% | 1.50% | 6.40% | 8.00% | 6.70% | 9.10% | 2.70% | 3.20% | 0.50% | 0.90% |  |  |  |  |  |  |  |  |  |  |
Weighted average life |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 2.6 | 2.6 | 3.5 | 3.3 | 3.9 | 3.8 | 3.9 | 4.2 | 1.2 | 1.8 |  |  |  |  |  |  |  |  |  |  |
Investment in closed end fund |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 21,000,000 |  |  |  |  |  |  |  |  |
Senior Notes, Carrying value |  |  |  |  |  |  |  | 100,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Senior notes interest rate |  |  |  |  |  |  |  | 5.875% |  |  | 5.75% |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument maturity date |  |  |  |  |  |  |  | February 15, 2013 |  |  | March 15, 2020 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Senior Notes, Fair value |  |  |  |  |  |  |  |  | 103,500,000 | 103,400,000 |  | 262,000,000 | 263,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Debt instrument, Face amount |  |  |  |  |  |  |  |  |  |  | 250,000,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Net unrealized gains (losses) recognized in earnings | 36,061,000 | 28,067,000 |  | 35,300,000 | 28,100,000 | (2,100,000) | (42,700,000) |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |
Investments redeemable in part, on a monthly basis, or in whole over a three month period |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 245,100,000 |  |  |  |  |  |  |  |  |
Assets and (liabilities) at fair value | 53,504,000 |  | 16,071,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 13,936,000 | 10,644,000 | (1,068,000) | (6,162,000) | (1,481,000) | (6,869,000) | (1,500,000)
Estimated liquidation period of limited partnership assets, Minimum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 7 years |  |  |  |  |  |  |  |  |  |
Estimated liquidation period of limited partnership assets, Maximum |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 10 years |  |  |  |  |  |  |  |  |  |
Other investments measured using net asset valuations | 709,615,000 |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | 389,451,000 | 266,141,000 | 31,713,000 | 22,310,000 |  |  |  |  |  |  |
Hedge fund side pocket investments |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  |  | $ 6,700,000 |  |  |  |  |  |  |

X
- Definition This item represents the weighted average life in years of debt securities. + References No definition available. + Details
Name: | rnr_DebtSecuritiesWeightedAverageLife
Namespace Prefix: | rnr_
Data Type: | xbrli:decimalItemType
Balance Type: | na
Period Type: | instant

X
- Definition Estimated Liquidation Period of Limited Partnership Assets, Maximum + References No definition available. + Details
Name: | rnr_EstimatedLiquidationPeriodOfLimitedPartnershipAssetsMaximum
Namespace Prefix: | rnr_
Data Type: | us-types:durationStringItemType
Balance Type: | na
Period Type: | duration

X
- Definition Estimated Liquidation Period of Limited Partnership Assets, Minimum + References No definition available. + Details
Name: | rnr_EstimatedLiquidationPeriodOfLimitedPartnershipAssetsMinimum
Namespace Prefix: | rnr_
Data Type: | us-types:durationStringItemType
Balance Type: | na
Period Type: | duration

X
- Definition This item represents senior secured bank loan funds in a closed end fund, which the Company has no right to redeem. + References No definition available. + Details
Name: | rnr_InvestmentInClosedEndFund
Namespace Prefix: | rnr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the fair value of investments redeemable in part, on a monthly basis, or in whole over a three month period. + References No definition available. + Details
Name: | rnr_InvestmentsRedeemableInPartMonthlyInTotalOverThreeMonths
Namespace Prefix: | rnr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents 'side pocket' investments which are not redeemable at the option of the shareholder. + References No definition available. + Details
Name: | rnr_NonredeemableSidePocketInvestments
Namespace Prefix: | rnr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Total Other Assets And liabilities Measured on Recurring Basis + References No definition available. + Details
Name: | rnr_TotalOtherAssetsAndLiabilitiesMeasuredOnRecurringBasis
Namespace Prefix: | rnr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition This item represents the weighted average effective yield percentage of debt securities. + References No definition available. + Details
Name: | rnr_WeightedAverageEffectiveYield
Namespace Prefix: | rnr_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition This element represents the total fair market value of investments in certain entities that calculate net asset value per share (including by unit, membership interest, or other equity (ownership interest) unit measure) (alternative investments). This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements, but may also be used in both the balance sheet and disclosure in the same submission. This item represents alternative investments as of the balance sheet date which may include investments in certain hedge funds, venture capital funds, private equity funds, real estate partnerships or funds, and any other investment in which investee management calculates net asset value per share as the primary metric for investment value. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 2 -Subparagraph a -URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19207-110258 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Paragraph 5 -Subparagraph a -URI http://asc.fasb.org/extlink&oid=6925170&loc=d3e19296-110258 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 820 -SubTopic 10 -Section 50 -Subparagraph (a) -Paragraph 6A -URI http://asc.fasb.org/extlink&oid=6925170&loc=SL6742756-110258 + Details
Name: | us-gaap_AlternativeInvestmentsFairValueDisclosure
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition The stated principal amount of the debt instrument at time of issuance, which may vary from the carrying amount because of unamortized premium or discount. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher AICPA -Name Accounting Principles Board Opinion (APB) -Number 21 -Paragraph 16, 20 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 45 -Paragraph 2 -URI http://asc.fasb.org/extlink&oid=6451184&loc=d3e28551-108399 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 835 -SubTopic 30 -Section 55 -Paragraph 8 -URI http://asc.fasb.org/extlink&oid=6584090&loc=d3e28878-108400 + Details
Name: | us-gaap_DebtInstrumentFaceAmount
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Interest rate stated in the contractual debt agreement. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(1)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentInterestRateStatedPercentage
Namespace Prefix: | us-gaap_
Data Type: | num:percentItemType
Balance Type: | na
Period Type: | instant

X
- Definition Description of the maturity date of the debt instrument including whether the debt matures serially and, if so, a brief description of the serial maturities. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 129 -Paragraph 2, 4 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 02 -Paragraph 22 -Article 5 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 210 -SubTopic 10 -Section S99 -Paragraph 1 -Subparagraph (SX 210.5-02.22(a)(2)) -URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682 + Details
Name: | us-gaap_DebtInstrumentMaturityDateDescription
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration

X
- Definition The fair value amount of long-term debt whether such amount is presented as a separate caption or as a parenthetical disclosure. Additionally, this element may be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements. The element may be used in both the balance sheet and disclosure in the same submission. + References No definition available. + Details
Name: | us-gaap_LongTermDebtFairValue
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition Including the current and noncurrent portions, carrying value as of the balance sheet date of Notes with the highest claim on the assets of the issuer in case of bankruptcy or liquidation (with maturities initially due after one year or beyond the operating cycle if longer). Senior note holders are paid off in full before any payments are made to junior note holders. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher SEC -Name Regulation S-X (SX) -Number 210 -Section 03 -Paragraph 16 -Article 9 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 942 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.9-03.16) -URI http://asc.fasb.org/extlink&oid=6876686&loc=d3e534808-122878 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 944 -SubTopic 210 -Section S99 -Paragraph 1 -Subparagraph (SX 210.7-03.16(a)) -URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910 + Details
Name: | us-gaap_SeniorNotes
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | instant

X
- Definition The net change in the difference between the fair value and the carrying value, or in the comparative fair values, of investments, not including unrealized gains or losses on securities separately or otherwise categorized as trading, available-for-sale, or held-to-maturity, held at each balance sheet date and included in earnings for the period. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Statement of Financial Accounting Standard (FAS) -Number 95 -Paragraph 28 -LegacyDoc This reference is SUPERSEDED by the Accounting Standards Codification effective for interim and annual periods ending after September 15, 2009. This reference is included to help users transition from the previous accounting hierarchy and will be removed from future versions of this taxonomy. Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 230 -SubTopic 10 -Section 45 -Paragraph 28 -Subparagraph (b) -URI http://asc.fasb.org/extlink&oid=6943989&loc=d3e3602-108585 + Details
Name: | us-gaap_UnrealizedGainLossOnInvestments
Namespace Prefix: | us-gaap_
Data Type: | xbrli:monetaryItemType
Balance Type: | credit
Period Type: | duration