Condensed Consolidating Financial Information Provided in Connection with Outstanding Debt of Subsidiaries (Condensed Consolidating Statement of Cash Flows) (Details) - USD ($) $ in Thousands	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Cash flows (used in) provided by operating activities
Net cash provided by (used in) operating activities	$ 475,466	$ 377,149
Cash flows used in investing activities
Proceeds from sales and maturities of fixed maturity investments trading	3,661,294	4,600,808
Purchases of fixed maturity investments trading	(3,370,394)	(3,519,277)
Net purchases of equity investments trading	(44,514)	(4,601)
Net purchases of short term investments	(704,226)	(1,374,632)
Net purchases of other investments	(79,711)	(51,811)
Net purchases of investments in other ventures	(1,888)	(1,573)
Return of investment from investment in other ventures	9,157	11,250
Dividends and return of capital from subsidiaries	0	0
Contributions to subsidiaries	0	0
Due to (from) subsidiary	0	0
Net purchase of TMR	0	(276,206)
Net cash used in investing activities	(530,282)	(616,042)
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	(15,359)	(14,469)
Dividends paid – preference shares	(9,056)	(9,189)
RenaissanceRe common share repurchases	(62,621)	0
Redemption of 6.08% Series C preference shares	(125,000)	0
Repayment of debt	(250,000)	0
Drawdown of RenaissanceRe Revolving Credit Facility	0	200,000
Net third party redeemable noncontrolling interest share transactions	42,599	(16,847)
Taxes paid on withholding shares	(10,180)	(6,957)
Net cash (used in) provided by financing activities	(429,617)	152,538
Effect of exchange rate changes on foreign currency cash	1,581	(292)
Net decrease in cash and cash equivalents	(482,852)	(86,647)
Cash and cash equivalents, beginning of period	1,379,068	1,107,922
Cash and cash equivalents, end of period	896,216	1,021,275
Reportable Legal Entities | RenaissanceRe Finance Inc. (Subsidiary Issuer)
Cash flows (used in) provided by operating activities
Net cash provided by (used in) operating activities	(21,068)	(21,202)
Cash flows used in investing activities
Proceeds from sales and maturities of fixed maturity investments trading	2,493	29,861
Purchases of fixed maturity investments trading	(17,602)	(14,098)
Net purchases of equity investments trading	0	0
Net purchases of short term investments	278,258	(4,946)
Net purchases of other investments	0	0
Net purchases of investments in other ventures	0	0
Return of investment from investment in other ventures	0	0
Dividends and return of capital from subsidiaries	0	0
Contributions to subsidiaries	0	0
Due to (from) subsidiary	15,277	6,629
Net purchase of TMR		0
Net cash used in investing activities	278,426	17,446
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	0	0
Dividends paid – preference shares	0	0
RenaissanceRe common share repurchases	0
Redemption of 6.08% Series C preference shares	0
Repayment of debt	(250,000)
Drawdown of RenaissanceRe Revolving Credit Facility		0
Net third party redeemable noncontrolling interest share transactions	0	0
Taxes paid on withholding shares	0	0
Net cash (used in) provided by financing activities	(250,000)	0
Effect of exchange rate changes on foreign currency cash	0	0
Net decrease in cash and cash equivalents	7,358	(3,756)
Cash and cash equivalents, beginning of period	8,731	9,604
Cash and cash equivalents, end of period	16,089	5,848
Reportable Legal Entities | RenaissanceRe Holdings Ltd. (Parent Guarantor)
Cash flows (used in) provided by operating activities
Net cash provided by (used in) operating activities	6,839	(317,296)
Cash flows used in investing activities
Proceeds from sales and maturities of fixed maturity investments trading	0	277,030
Purchases of fixed maturity investments trading	0	(35,909)
Net purchases of equity investments trading	0	0
Net purchases of short term investments	(85,628)	(54,622)
Net purchases of other investments	0	0
Net purchases of investments in other ventures	0	0
Return of investment from investment in other ventures	0	0
Dividends and return of capital from subsidiaries	216,243	487,264
Contributions to subsidiaries	(64,952)	(528,416)
Due to (from) subsidiary	126,320	2,100
Net purchase of TMR		0
Net cash used in investing activities	191,983	147,447
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	(15,359)	(14,469)
Dividends paid – preference shares	(9,056)	(9,189)
RenaissanceRe common share repurchases	(62,621)
Redemption of 6.08% Series C preference shares	(125,000)
Repayment of debt	0
Drawdown of RenaissanceRe Revolving Credit Facility		200,000
Net third party redeemable noncontrolling interest share transactions	0	0
Taxes paid on withholding shares	(10,180)	(6,957)
Net cash (used in) provided by financing activities	(222,216)	169,385
Effect of exchange rate changes on foreign currency cash	0	0
Net decrease in cash and cash equivalents	(23,394)	(464)
Cash and cash equivalents, beginning of period	26,460	3,534
Cash and cash equivalents, end of period	3,066	3,070
Reportable Legal Entities | Other RenaissanceRe Holdings Ltd. Subsidiaries and Eliminations (Non-Guarantor Subsidiaries)
Cash flows (used in) provided by operating activities
Net cash provided by (used in) operating activities	489,695	715,647
Cash flows used in investing activities
Proceeds from sales and maturities of fixed maturity investments trading	3,658,801	4,293,917
Purchases of fixed maturity investments trading	(3,352,792)	(3,469,270)
Net purchases of equity investments trading	(44,514)	(4,601)
Net purchases of short term investments	(896,856)	(1,315,064)
Net purchases of other investments	(79,711)	(51,811)
Net purchases of investments in other ventures	(1,888)	(1,573)
Return of investment from investment in other ventures	9,157	11,250
Dividends and return of capital from subsidiaries	(216,243)	(487,264)
Contributions to subsidiaries	64,952	528,416
Due to (from) subsidiary	(141,597)	(8,729)
Net purchase of TMR		(276,206)
Net cash used in investing activities	(1,000,691)	(780,935)
Cash flows (used in) provided by financing activities
Dividends paid – RenaissanceRe common shares	0	0
Dividends paid – preference shares	0	0
RenaissanceRe common share repurchases	0
Redemption of 6.08% Series C preference shares	0
Repayment of debt	0
Drawdown of RenaissanceRe Revolving Credit Facility		0
Net third party redeemable noncontrolling interest share transactions	42,599	(16,847)
Taxes paid on withholding shares	0	0
Net cash (used in) provided by financing activities	42,599	(16,847)
Effect of exchange rate changes on foreign currency cash	1,581	(292)
Net decrease in cash and cash equivalents	(466,816)	(82,427)
Cash and cash equivalents, beginning of period	1,343,877	1,094,784
Cash and cash equivalents, end of period	$ 877,061	$ 1,012,357