Decrease in noncontrolling interest (for example, but not limited to, redeeming or purchasing the interests of noncontrolling shareholders, issuance of shares (interests) by the non-wholly owned subsidiary to the parent entity for other than cash, and a buyback of shares (interest) by the non-wholly owned subsidiary from the noncontrolling interests).

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 23
-URI http://asc.fasb.org/extlink&oid=108774443&loc=SL4569655-111683

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 24
-URI http://asc.fasb.org/extlink&oid=108774443&loc=SL4616395-111683

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

+ Details

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

- Definition

The parent entity's interest in net assets of the subsidiary, expressed as a percentage.

+ References

No definition available.

+ Details

Name:	us-gaap_MinorityInterestOwnershipPercentageByParent
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount of increase in noncontrolling interest from sale of a portion of the parent's controlling interest.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=109239629&loc=SL4573702-111684

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 23
-URI http://asc.fasb.org/extlink&oid=108774443&loc=SL4569655-111683

+ Details

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

- Definition

Amount of increase in noncontrolling interest from subsidiary issuance of equity interests to noncontrolling interest holders.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 1A
-Subparagraph (c)(2)
-URI http://asc.fasb.org/extlink&oid=109239629&loc=SL4573702-111684

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 45
-Paragraph 23
-URI http://asc.fasb.org/extlink&oid=108774443&loc=SL4569655-111683

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

+ Details

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

- Definition

Cash outflow to owners or shareholders, excluding ordinary dividends. Includes special dividends.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 15
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3291-108585

+ Details

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

- Definition

The cash outflow associated with the acquisition of or advances to an entity that is related to it but not strictly controlled (for example, an unconsolidated subsidiary, affiliate, and joint venture or equity method investment) or the acquisition of an additional interest in a subsidiary (controlled entity).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 13
-Subparagraph (b)
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3213-108585

+ Details

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

- Definition

Number of shares that have been repurchased during the period and have not been retired and are not held in treasury. Some state laws may govern the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

Name:	us-gaap_StockRepurchasedDuringPeriodShares
Namespace Prefix:	us-gaap_
Data Type:	xbrli:sharesItemType
Balance Type:	na
Period Type:	duration

- Definition

Equity impact of the value of stock that has been repurchased during the period and has not been retired and is not held in treasury. Some state laws may mandate the circumstances under which an entity may acquire its own stock and prescribe the accounting treatment therefore. This element is used when state law does not recognize treasury stock.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(28))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section 50
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=109259400&loc=d3e21463-112644

Reference 3: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.3-04)
-URI http://asc.fasb.org/extlink&oid=120397183&loc=d3e187085-122770

Reference 4: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(29))
-URI http://asc.fasb.org/extlink&oid=120391452&loc=d3e13212-122682

+ Details

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

- Definition

Detail information of subsequent event by type. User is expected to use existing line items from elsewhere in the taxonomy as the primary line items for this disclosure, which is further associated with dimension and member elements pertaining to a subsequent event.

+ References

No definition available.

+ Details

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

- Definition

Total cost of shares repurchased divided by the total number of shares repurchased.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 505
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=6405813&loc=d3e23239-112655

+ Details

Name:	us-gaap_TreasuryStockAcquiredAverageCostPerShare
Namespace Prefix:	us-gaap_
Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

Percentage of the Variable Interest Entity's (VIE) voting interest owned by (or beneficial interest in) the reporting entity (directly or indirectly).

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 810
-SubTopic 10
-Section 50
-Paragraph 5A
-Subparagraph (d)
-URI http://asc.fasb.org/extlink&oid=121559654&loc=SL6759159-111685

+ Details

Name:	us-gaap_VariableInterestEntityOwnershipPercentage
Namespace Prefix:	us-gaap_
Data Type:	num:percentItemType
Balance Type:	na
Period Type:	duration

- Details

Name:	srt_OwnershipAxis=rnr_DaVinciReinsuranceLtd.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_CommonStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=rnr_DaVinciReinsuranceLtd.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_SubsequentEventTypeAxis=us-gaap_SubsequentEventMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_OwnershipAxis=rnr_DaVinciReHoldingsLtd.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=rnr_ThirdPartyInvestorsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=rnr_DaVinciReHoldingsLtd.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=rnr_DaVinciReHoldingsLtd.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=rnr_RenaissanceReHoldingsLtd.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	dei_LegalEntityAxis=rnr_UpsilonRFOReLtd.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_ConsolidatedEntitiesAxis=us-gaap_VariableInterestEntityPrimaryBeneficiaryMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_StatementClassOfStockAxis=us-gaap_PreferredStockMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_CounterpartyNameAxis=us-gaap_InvestorMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BalanceSheetLocationAxis=us-gaap_OtherLiabilitiesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Subsequent Events (Details) - USD ($) $ / shares in Units, $ in Thousands				1 Months Ended			12 Months Ended
	Jan. 01, 2021	Jan. 01, 2020	Jun. 01, 2019	Feb. 04, 2021	Jan. 31, 2021	Dec. 31, 2020	Dec. 31, 2020	Dec. 31, 2019
DaVinci Reinsurance Ltd.
Subsequent Event [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent		21.40%	21.90%			21.40%	21.40%	21.90%
Common shares
Subsequent Event [Line Items]
Share repurchase program, shares repurchased (in shares)							405,682
Repurchase of shares							$ 62,600
Share repurchase program, price per share (in dollars per share)							$ 154.36
DaVinci Reinsurance Ltd.
Subsequent Event [Line Items]
Noncontrolling interest, increase from sale of parent equity interest		$ 10,000	$ 11,600
Subsequent Event \| DaVinciRe Holdings Ltd.
Subsequent Event [Line Items]
Noncontrolling Interest, Ownership Percentage by Parent	28.70%
Subsequent Event \| Common shares
Subsequent Event [Line Items]
Share repurchase program, shares repurchased (in shares)				250,169
Repurchase of shares				$ 38,700
Share repurchase program, price per share (in dollars per share)				$ 154.75
Subsequent Event \| Third-Party Investors
Subsequent Event [Line Items]
Redemption of shares from redeemable noncontrolling interests	$ 156,700
Subsequent Event \| DaVinciRe Holdings Ltd.
Subsequent Event [Line Items]
Noncontrolling interest, increase from sale of parent equity interest	40,000
DaVinciRe Holdings Ltd.
Subsequent Event [Line Items]
Noncontrolling interest, value subscribed			349,200				$ 9,991	$ 274,699
Redemption of shares from redeemable noncontrolling interests							(1,450)	1,148
DaVinciRe Holdings Ltd. \| Third-Party Investors
Subsequent Event [Line Items]
Noncontrolling interest, value subscribed			263,100
DaVinciRe Holdings Ltd. \| RenaissanceRe Holdings Ltd.
Subsequent Event [Line Items]
Noncontrolling interest, value subscribed			$ 86,100
DaVinciRe Holdings Ltd. \| Subsequent Event
Subsequent Event [Line Items]
Noncontrolling interest, value subscribed	250,000
DaVinciRe Holdings Ltd. \| Subsequent Event \| Third-Party Investors
Subsequent Event [Line Items]
Noncontrolling interest, value subscribed	150,900
DaVinciRe Holdings Ltd. \| Subsequent Event \| RenaissanceRe Holdings Ltd.
Subsequent Event [Line Items]
Noncontrolling interest, value subscribed	$ 99,100
Upsilon RFO Re Ltd. \| RenaissanceRe Holdings Ltd. \| Primary Beneficiary
Subsequent Event [Line Items]
Payments of capital distributions							$ 102,900	$ 31,000
Variable interest entity, ownership percentage							13.80%	16.50%
Upsilon RFO Re Ltd. \| RenaissanceRe Holdings Ltd. \| Primary Beneficiary \| Preference shares
Subsequent Event [Line Items]
Investment in variable interest entity							$ 98,100	$ 100,000
Upsilon RFO Re Ltd. \| Investor \| Primary Beneficiary
Subsequent Event [Line Items]
Payments of capital distributions							586,000	279,200
Upsilon RFO Re Ltd. \| Investor \| Primary Beneficiary \| Preference shares
Subsequent Event [Line Items]
Investment in variable interest entity						$ 620,300	835,900	$ 618,700
Upsilon RFO Re Ltd. \| Investor \| Primary Beneficiary \| Preference shares \| Other liabilities
Subsequent Event [Line Items]
Investment in variable interest entity							$ 550,000
Upsilon RFO Re Ltd. \| Subsequent Event \| RenaissanceRe Holdings Ltd. \| Primary Beneficiary
Subsequent Event [Line Items]
Variable interest entity, ownership percentage	12.40%
Upsilon RFO Re Ltd. \| Subsequent Event \| RenaissanceRe Holdings Ltd. \| Primary Beneficiary \| Preference shares
Subsequent Event [Line Items]
Investment in variable interest entity	$ 32,300
Upsilon RFO Re Ltd. \| Subsequent Event \| Investor \| Primary Beneficiary
Subsequent Event [Line Items]
Payments of capital distributions					$ 150,000
Upsilon RFO Re Ltd. \| Subsequent Event \| Investor \| Primary Beneficiary \| Preference shares
Subsequent Event [Line Items]
Investment in variable interest entity	$ 470,300