Variable Interest Entities - Narrative (Details)		1 Months Ended	3 Months Ended	12 Months Ended
	Jan. 10, 2023 note	Jul. 31, 2023 USD ($)	Mar. 31, 2023 USD ($)	Dec. 31, 2023 USD ($) account	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Jun. 29, 2021 USD ($)	Jan. 10, 2020 USD ($)
Variable Interest Entity [Line Items]
Number of segregated accounts | account				4
Total assets				$ 49,007,105,000	$ 36,552,878,000
Total liabilities				33,451,316,000	26,692,215,000
Investments in other ventures, under equity method (Note 5)				112,624,000	79,750,000
Redeemable noncontrolling interest, equity, carrying amount				6,100,831,000	4,535,389,000
Ceded premiums written				1,394,553,000	2,017,380,000	$ 1,894,423,000
Ceded premiums earned				1,614,432,000	1,850,807,000	1,863,350,000
Vermeer Reinsurance Ltd.
Variable Interest Entity [Line Items]
Redeemable noncontrolling interest, equity, carrying amount				1,555,297,000	1,490,840,000	1,197,782,000
Fontana Holdings L.P.
Variable Interest Entity [Line Items]
Redeemable noncontrolling interest, equity, carrying amount				353,823,000	268,031,000	0
Primary Beneficiary | Upsilon RFO Re Ltd.
Variable Interest Entity [Line Items]
Total assets				2,400,000,000	3,700,000,000
Total liabilities				2,400,000,000	3,700,000,000
Net assets				74,200,000	165,300,000
Primary Beneficiary | Investors of Upsilon RFO Diversified I, II and III | Upsilon RFO Re Ltd.
Variable Interest Entity [Line Items]
Payments of capital distributions				988,500,000
Net assets				500,000,000	1,200,000,000
Primary Beneficiary | Investors of Upsilon RFO Diversified I, II and III | Upsilon RFO Re Ltd. | Preference shares
Variable Interest Entity [Line Items]
Investment in variable interest entity				39,800,000
Primary Beneficiary | RenaissanceRe Holdings Ltd. | Upsilon RFO Re Ltd.
Variable Interest Entity [Line Items]
Payments of capital distributions				$ 125,500,000	$ 83,100,000
Variable interest entity, ownership percentage				14.30%	12.70%
Primary Beneficiary | RenaissanceRe Holdings Ltd. | Upsilon RFO Re Ltd. | Preference shares
Variable Interest Entity [Line Items]
Investment in variable interest entity				$ 10,200,000	$ 10,000,000
Primary Beneficiary | Investor | Upsilon RFO Re Ltd.
Variable Interest Entity [Line Items]
Payments of capital distributions					508,900,000
Primary Beneficiary | Investor | Upsilon RFO Re Ltd. | Preference shares
Variable Interest Entity [Line Items]
Investment in variable interest entity					89,000,000
Not Primary Beneficiary | RenaissanceRe Upsilon Diversified Fund
Variable Interest Entity [Line Items]
Investments in other ventures, under equity method (Note 5)				800,000	1,900,000
Not Primary Beneficiary | NOC1
Variable Interest Entity [Line Items]
Investments in other ventures, under equity method (Note 5)				1,700,000
Not Primary Beneficiary | Alpha Cat entities
Variable Interest Entity [Line Items]
Investments in other ventures, under equity method (Note 5)				4,400,000
Not Primary Beneficiary | RenaissanceRe Upsilon Diversified Fund
Variable Interest Entity [Line Items]
Total assets				600,800,000	1,200,000,000
Total liabilities				108,000,000.0	32,100,000
Not Primary Beneficiary | RenaissanceRe Upsilon Diversified Fund | Upsilon RFO Re Ltd.
Variable Interest Entity [Line Items]
Investment owned, fair value				503,100,000	1,200,000,000
Not Primary Beneficiary | NOC1
Variable Interest Entity [Line Items]
Total assets				196,500,000
Total liabilities				22,800,000
Not Primary Beneficiary | Vermeer Reinsurance Ltd.
Variable Interest Entity [Line Items]
Total assets				1,700,000,000	1,600,000,000
Total liabilities				102,700,000	144,900,000
Redeemable noncontrolling interest, equity, carrying amount				1,600,000,000	1,500,000,000
Not Primary Beneficiary | Fontana Holdings L.P.
Variable Interest Entity [Line Items]
Total assets				1,500,000,000	711,000,000
Total liabilities				968,500,000	319,200,000
Redeemable noncontrolling interest, equity, carrying amount				353,800,000	268,000,000
Not Primary Beneficiary | Mona Lisa Re
Variable Interest Entity [Line Items]
Total assets				436,900,000	654,800,000
Total liabilities				436,900,000	654,800,000
Face amount							$ 250,000,000
Number of variable notes issued | note	2
Not Primary Beneficiary | Mona Lisa Re | Other investments
Variable Interest Entity [Line Items]
Fair value of investment				2,200,000	5,700,000
Not Primary Beneficiary | Mona Lisa Re | $250 Million Principal-At-Risk Note
Variable Interest Entity [Line Items]
Face amount								$ 250,000,000
Not Primary Beneficiary | Mona Lisa Re | $150 Million Principal-At-Risk Note
Variable Interest Entity [Line Items]
Face amount								$ 150,000,000
Not Primary Beneficiary | Tailwind Re Ltd
Variable Interest Entity [Line Items]
Total assets				417,100,000
Total liabilities				417,100,000
Not Primary Beneficiary | Tailwind Re Ltd | Other investments
Variable Interest Entity [Line Items]
Fair value of investment				800,000
Not Primary Beneficiary | Alpha Cat entities
Variable Interest Entity [Line Items]
Total assets				5,000,000,000
Total liabilities				2,400,000,000
Not Primary Beneficiary | RenaissanceRe Holdings Ltd. | RenaissanceRe Upsilon Diversified Fund
Variable Interest Entity [Line Items]
Payments of capital distributions				1,200,000	0
Not Primary Beneficiary | RenaissanceRe Holdings Ltd. | RenaissanceRe Upsilon Diversified Fund | Preference shares
Variable Interest Entity [Line Items]
Investment in variable interest entity				100,000	0
Not Primary Beneficiary | RenaissanceRe Holdings Ltd. | NOC1 | Preference shares
Variable Interest Entity [Line Items]
Investment in variable interest entity				1,600,000
Not Primary Beneficiary | RenaissanceRe Holdings Ltd. | Langhorne Holdings LLC
Variable Interest Entity [Line Items]
Payments of capital distributions		$ 800,000	$ 1,500,000
Not Primary Beneficiary | Investors of Upsilon RFO Diversified IV | Upsilon RFO Re Ltd.
Variable Interest Entity [Line Items]
Net assets					88,300,000
Not Primary Beneficiary | Investors of Upsilon RFO Diversified IV | Upsilon RFO Re Ltd. | Preference shares
Variable Interest Entity [Line Items]
Investment in variable interest entity				81,400,000
Not Primary Beneficiary | Investor | RenaissanceRe Upsilon Diversified Fund
Variable Interest Entity [Line Items]
Payments of capital distributions				844,100,000	143,500,000
Not Primary Beneficiary | Investor | RenaissanceRe Upsilon Diversified Fund | Preference shares
Variable Interest Entity [Line Items]
Investment in variable interest entity				30,000,000.0	82,500,000
Not Primary Beneficiary | Investor | NOC1 | Preference shares
Variable Interest Entity [Line Items]
Investment in variable interest entity				161,500,000
Not Primary Beneficiary | Renaissance Reinsurance | Mona Lisa Re
Variable Interest Entity [Line Items]
Ceded premiums written				32,800,000	39,600,000	39,500,000
Ceded premiums earned				32,800,000	39,400,000	32,500,000
Not Primary Beneficiary | DaVinci Reinsurance | Mona Lisa Re
Variable Interest Entity [Line Items]
Ceded premiums written				8,200,000	9,900,000	9,900,000
Ceded premiums earned				8,200,000	$ 9,800,000	$ 8,100,000
Not Primary Beneficiary | Validus | Tailwind Re Ltd
Variable Interest Entity [Line Items]
Ceded premiums written				0
Ceded premiums earned				$ 6,500,000