v2.4.0.6

Derivative Instruments (Narrative) (Details) (USD $) In Millions, unless otherwise specified | Mar. 31, 2013 | Dec. 31, 2012
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Interest Rate Contract [Member] |  |
Derivative [Line Items] |  |
Notional amount of interest rate derivative purchase contracts | $ 434.1 | $ 377.8
Notional amount of interest rate derivative sale contracts | 317.6 | 310.7
Foreign Currency Forward Contracts, Underwriting and Non-investment Operations [Member] |  |
Derivative [Line Items] |  |
Notional amount of foreign currency derivative purchase contracts | 417.4 | 446.2
Notional amount of foreign currency derivative sale contracts | 230.6 | 119.5
Foreign Currency Forward Contracts, Investment Operations [Member] |  |
Derivative [Line Items] |  |
Notional amount of foreign currency derivative purchase contracts | 275.2 | 176.7
Notional amount of foreign currency derivative sale contracts | 314.9 | 217.4
Foreign Currency Forward Contracts, Energy And Risk Operations [Member] |  |
Derivative [Line Items] |  |
Notional amount of foreign currency derivative purchase contracts | 0 | 0
Notional amount of foreign currency derivative sale contracts | 47.4 | 38.2
Credit Risk Contract [Member] |  |
Derivative [Line Items] |  |
Notional amount of credit risk derivative purchase contracts | 4.7 | 46.1
Notional amount of credit risk derivative sale contracts | $ 27.2 | $ 24.0

X
- Definition Aggregate notional amount of credit derivatives purchased to manage exposure to credit risk. Notional amount refers to the number of contracts multiplied by the contract size as specified in the credit derivative contract. + References No definition available. + Details
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Namespace Prefix: | rnr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Aggregate notional amount of credit derivatives sold to manage exposure to credit risk. Notional amount refers to the number of contracts multiplied by the contract size as specified in the credit derivative contract. + References No definition available. + Details
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X
- Definition Aggregate notional amount of interest rate futures contracts purchased to manage exposure to interest rate risk. Notional amount refers to the number of contracts multiplied by the contract size as specified in the interest rate futures contract. + References No definition available. + Details
Name: | rnr_NotionalAmountOfInterestRateDerivativePurchaseContracts
Namespace Prefix: | rnr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Definition Aggregate notional amount of interest rate futures contracts sold to manage exposure to interest rate risk. Notional amount refers to the number of contracts multiplied by the contract size as specified in the interest rate futures contract. + References No definition available. + Details
Name: | rnr_NotionalAmountOfInterestRateDerivativeSaleContracts
Namespace Prefix: | rnr_
Data Type: | xbrli:monetaryItemType
Balance Type: | debit
Period Type: | instant

X
- Details
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Data Type: | xbrli:stringItemType
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Period Type: | duration

X
- Definition Aggregate notional amount of foreign currency derivatives to purchase a foreign currency. Notional amount refers to the number of currency units specified in the foreign currency derivative contract. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5579245-113959 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Notional Amount -URI http://asc.fasb.org/extlink&oid=6519104 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5580258-113959 + Details
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Period Type: | instant

X
- Definition Aggregate notional amount of foreign currency derivatives to sell a foreign currency. Notional amount refers to the number of currency units specified in the foreign currency derivative contract. + References Reference 1: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1A -Subparagraph (d) -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5579245-113959 Reference 2: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Glossary Notional Amount -URI http://asc.fasb.org/extlink&oid=6519104 Reference 3: http://www.xbrl.org/2003/role/presentationRef -Publisher FASB -Name Accounting Standards Codification -Topic 815 -SubTopic 10 -Section 50 -Paragraph 1B -URI http://asc.fasb.org/extlink&oid=7476318&loc=SL5580258-113959 + Details
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