VARIABLE INTEREST ENTITIES (Details)		3 Months Ended
	Jan. 10, 2023 USD ($) note	Mar. 31, 2023 USD ($)	Mar. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Variable Interest Entity [Line Items]
Assets		$ 38,270,327,000		$ 36,552,878,000
Liabilities		27,047,406,000		26,692,215,000
Redeemable noncontrolling interests		5,357,386,000		4,535,389,000
Ceded premiums written		526,558,000	$ 777,747,000
Ceded premiums earned		417,138,000	446,604,000
Investments in other ventures, under equity method		84,731,000		79,750,000
Vermeer Reinsurance Ltd.
Variable Interest Entity [Line Items]
Redeemable noncontrolling interests		1,538,245,000	1,246,480,000	1,490,840,000	$ 1,197,782,000
Fontana
Variable Interest Entity [Line Items]
Redeemable noncontrolling interests		276,859,000	0	268,031,000	0
Medici
Variable Interest Entity [Line Items]
Redeemable noncontrolling interests		1,307,741,000	941,912,000	1,036,218,000	$ 856,820,000
Variable Interest Entity, Primary Beneficiary | Upsilon RFO Re Ltd.
Variable Interest Entity [Line Items]
Assets		3,400,000,000		3,700,000,000
Liabilities		3,400,000,000		3,700,000,000
Net assets		200,000,000		200,000,000
Variable Interest Entity, Primary Beneficiary | Upsilon RFO Re Ltd. | Third party investor
Variable Interest Entity [Line Items]
Payments of capital distribution		160,100,000	22,900,000
Net assets		1,100,000,000		1,200,000,000
Variable Interest Entity, Primary Beneficiary | Upsilon RFO Re Ltd. | Third party investor | Non-Voting Preference Shares
Variable Interest Entity [Line Items]
Contributions to subsidiaries		0	$ 89,000,000.0
Variable Interest Entity, Primary Beneficiary | Upsilon RFO Re Ltd. | RenaissanceRe Holdings Ltd.
Variable Interest Entity [Line Items]
Payments of capital distribution		$ 20,700,000
Variable interest entity, ownership percentage		12.60%	13.80%
Variable Interest Entity, Primary Beneficiary | Upsilon RFO Re Ltd. | RenaissanceRe Holdings Ltd. | Non-Voting Preference Shares
Variable Interest Entity [Line Items]
Contributions to subsidiaries			$ 10,000,000.0
Variable Interest Entity, Primary Beneficiary | Vermeer Reinsurance Ltd.
Variable Interest Entity [Line Items]
Assets		$ 1,700,000,000		1,600,000,000
Liabilities		168,000,000		144,900,000
Redeemable noncontrolling interests		1,500,000,000		1,500,000,000
Variable Interest Entity, Primary Beneficiary | Fontana
Variable Interest Entity [Line Items]
Assets		878,000,000
Liabilities		473,400,000
Redeemable noncontrolling interests		276,900,000
Variable Interest Entity, Not Primary Beneficiary | Mona Lisa Re
Variable Interest Entity [Line Items]
Assets		466,000,000		654,800,000
Liabilities		466,000,000		654,800,000
Number of variable rate notes issued | note	2
Variable Interest Entity, Not Primary Beneficiary | Mona Lisa Re | Term loans
Variable Interest Entity [Line Items]
Investment in participating notes		3,000,000		5,700,000
Variable Interest Entity, Not Primary Beneficiary | Mona Lisa Re | Eighty Five Million Principal At Risk Variable Rate Note
Variable Interest Entity [Line Items]
Face amount	$ 85,000,000
Variable Interest Entity, Not Primary Beneficiary | Mona Lisa Re | One Hundred Million Principal At Risk Variable Rate Note
Variable Interest Entity [Line Items]
Face amount	$ 100,000,000
Variable Interest Entity, Not Primary Beneficiary | Mona Lisa Re | Four Hundred Million Principal At Risk Variable Rate Note
Variable Interest Entity [Line Items]
Face amount		400,000,000
Variable Interest Entity, Not Primary Beneficiary | Mona Lisa Re | Renaissance Reinsurance Ltd.
Variable Interest Entity [Line Items]
Ceded premiums written		18,300,000	25,100,000
Ceded premiums earned		7,700,000	9,700,000
Variable Interest Entity, Not Primary Beneficiary | Mona Lisa Re | DaVinci Reinsurance Ltd.
Variable Interest Entity [Line Items]
Ceded premiums written		4,600,000	6,200,000
Ceded premiums earned		2,000,000	$ 2,400,000
Variable Interest Entity, Not Primary Beneficiary | Mona Lisa Re | Medici
Variable Interest Entity [Line Items]
Payments of capital distribution		16,500,000
Variable Interest Entity, Not Primary Beneficiary | Langhorne Partners
Variable Interest Entity [Line Items]
Investments in other ventures, under equity method		100,000		$ 100,000
Variable Interest Entity, Not Primary Beneficiary | Langhorne Holdings LLC | RenaissanceRe Holdings Ltd.
Variable Interest Entity [Line Items]
Payments of capital distribution		$ 1,500,000