No definition available.

Name:	rnr_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisForeignExchangeGainsLosses
Namespace Prefix:	rnr_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of gain (loss) recognized in income from asset and liability measured at fair value on recurring basis using unobservable input (level 3).

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(1)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

+ Details

Name:	us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisGainLossIncludedInEarnings
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- References

No definition available.

+ Details

Name:	us-gaap_FairValueAssetsAndLiabilitiesMeasuredOnRecurringBasisGainLossIncludedInEarningsAbstract
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.

+ References

No definition available.

+ Details

Name:	us-gaap_FairValueAssetsMeasuredOnRecurringBasisUnobservableInputReconciliationCalculationRollForward
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Amount of purchases of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2G
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2G

Reference 2: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 101
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-101

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-3

Reference 4: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetPurchases
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount of settlement of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 101
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-101

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)(2)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetSettlements
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Fair value of financial instrument classified as an asset measured using unobservable inputs that reflect the entity's own assumption about the assumptions market participants would use in pricing.

+ References

Reference 1: http://www.xbrl.org/2003/role/exampleRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 55
-Paragraph 101
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482078/820-10-55-101

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-3

Reference 3: http://www.xbrl.org/2003/role/disclosureRef
-Topic 820
-SubTopic 10
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147482106/820-10-50-2

+ Details

Name:	us-gaap_FairValueMeasurementWithUnobservableInputsReconciliationRecurringBasisAssetValue
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Indicates line item in statement of income or comprehensive income that includes gain (loss) from asset (liability), measured at fair value using unobservable input (level 3).

+ References

+ Details

Name:	us-gaap_FairValueRecurringBasisUnobservableInputReconciliationAssetLiabilityGainLossStatementOfIncomeExtensibleList
Namespace Prefix:	us-gaap_
Data Type:	enum2:enumerationSetItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	us-gaap_FairValueByMeasurementFrequencyAxis=us-gaap_FairValueMeasurementsRecurringMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_InvestmentIncomeMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_GainLossOnInvestmentsMember1
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_IncomeStatementLocationAxis=us-gaap_OtherOperatingIncomeExpenseMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByAssetClassAxis=us-gaap_AssetBackedSecuritiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByAssetClassAxis=us-gaap_PrivateEquityFundsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByAssetClassAxis=rnr_TermLoanMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FairValueByAssetClassAxis=rnr_OtherAssetsLiabilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

FAIR VALUE MEASUREMENTS - Schedule of Assets and Liabilities Measured at Fair Value on a Recurring Basis Using Level 3 Inputs (Details) - Fair Value, Measurements, Recurring - USD ($) $ in Thousands	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of the period	$ 38,753	$ 156,880	$ 43,372	$ 157,048
Included in net investment income
Net foreign exchange gains (losses)	29	1	43	(3)
Purchases	41,459		41,459	141
Settlements	(565)	(895)	(761)	(1,120)
Balance at end of the period	$ 76,094	$ 141,477	$ 76,094	$ 141,477
Net investment income
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Asset (Liability), Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net Investment Income		Net Investment Income	Net Investment Income
Included in net investment income
Included in earnings (loss)	$ 70		$ 139	$ 63
Net realized and unrealized gains (losses) on investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Asset (Liability), Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Net realized and unrealized gains (losses) on investments	Net realized and unrealized gains (losses) on investments	Net realized and unrealized gains (losses) on investments	Net realized and unrealized gains (losses) on investments
Included in net investment income
Included in earnings (loss)	$ (3,778)	$ (14,687)	$ (8,651)	$ (14,687)
Other income (loss)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Fair Value, Asset (Liability), Recurring Basis, Unobservable Input Reconciliation, Gain (Loss), Statement of Income or Comprehensive Income [Extensible Enumeration]	Other income (loss)	Other income (loss)	Other income (loss)	Other income (loss)
Included in net investment income
Included in earnings (loss)	$ 126	$ 178	$ 493	$ 35
Asset-backed
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of the period	0		0
Included in net investment income
Net foreign exchange gains (losses)	0		0
Purchases	41,459		41,459
Settlements	(523)		(523)
Balance at end of the period	40,936		40,936
Asset-backed \| Net investment income
Included in net investment income
Included in earnings (loss)	0		0
Asset-backed \| Net realized and unrealized gains (losses) on investments
Included in net investment income
Included in earnings (loss)	0		0
Asset-backed \| Other income (loss)
Included in net investment income
Included in earnings (loss)	0		0
Direct Private Equity Investments
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of the period	38,987	59,964	43,777	59,905
Included in net investment income
Net foreign exchange gains (losses)	29	1	43	(3)
Purchases	0		0	0
Settlements	0	0	0	0
Balance at end of the period	35,308	45,278	35,308	45,278
Direct Private Equity Investments \| Net investment income
Included in net investment income
Included in earnings (loss)	70		139	63
Direct Private Equity Investments \| Net realized and unrealized gains (losses) on investments
Included in net investment income
Included in earnings (loss)	(3,778)	(14,687)	(8,651)	(14,687)
Direct Private Equity Investments \| Other income (loss)
Included in net investment income
Included in earnings (loss)	0	0	0	0
Term Loans
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of the period		97,433		97,658
Included in net investment income
Net foreign exchange gains (losses)		0		0
Purchases				0
Settlements		(794)		(1,019)
Balance at end of the period		96,639		96,639
Term Loans \| Net investment income
Included in net investment income
Included in earnings (loss)				0
Term Loans \| Net realized and unrealized gains (losses) on investments
Included in net investment income
Included in earnings (loss)		0		0
Term Loans \| Other income (loss)
Included in net investment income
Included in earnings (loss)		0		0
Other Assets and (Liabilities)
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Balance at beginning of the period	(234)	(517)	(405)	(515)
Included in net investment income
Net foreign exchange gains (losses)	0	0	0	0
Purchases	0		0	141
Settlements	(42)	(101)	(238)	(101)
Balance at end of the period	(150)	(440)	(150)	(440)
Other Assets and (Liabilities) \| Net investment income
Included in net investment income
Included in earnings (loss)	0		0	0
Other Assets and (Liabilities) \| Net realized and unrealized gains (losses) on investments
Included in net investment income
Included in earnings (loss)	0	0	0	0
Other Assets and (Liabilities) \| Other income (loss)
Included in net investment income
Included in earnings (loss)	$ 126	$ 178	$ 493	$ 35