Noncontrolling Interests (Schedule of Redeemable Noncontrolling Interest Activity) (Details) - USD ($) $ in Thousands	9 Months Ended	12 Months Ended
Sep. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Activity in redeemable noncontrolling interest
Beginning balance	$ 3,388,319	$ 3,388,319
Net income (loss) attributable to redeemable noncontrolling interests		(63,285)	$ 230,653	$ 201,469
Ending balance		3,554,053	3,388,319
DaVinciRe Holdings Ltd.
Activity in redeemable noncontrolling interest
Beginning balance	1,560,693	1,560,693	1,435,581
Redemption of shares from redeemable noncontrolling interests, net of adjustments		(157,864)	1,450
Sale of shares to redeemable noncontrolling interests	250,000
Net income (loss) attributable to redeemable noncontrolling interests		(102,932)	113,671	127,084
Ending balance		1,499,451	1,560,693	1,435,581
DaVinciRe Holdings Ltd. \| Third-Party Investors And RenaissanceRe
Activity in redeemable noncontrolling interest
Sale of shares to redeemable noncontrolling interests		199,554	9,991
Medici
Activity in redeemable noncontrolling interest
Beginning balance	717,999	717,999	632,112
Redemption of shares from redeemable noncontrolling interests, net of adjustments		(64,191)	(107,386)
Sale of shares to redeemable noncontrolling interests		201,520	137,303
Net income (loss) attributable to redeemable noncontrolling interests		1,492	55,970	25,759
Ending balance		856,820	717,999	632,112
Vermeer Reinsurance Ltd.
Activity in redeemable noncontrolling interest
Beginning balance	$ 1,109,627	1,109,627	1,003,615
Sale of shares to redeemable noncontrolling interests		50,000	45,000
Net income (loss) attributable to redeemable noncontrolling interests		38,155	61,012	48,626
Ending balance		$ 1,197,782	$ 1,109,627	$ 1,003,615

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

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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).

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Amount of Net Income (Loss) attributable to redeemable noncontrolling interest.

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

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As of the reporting date, the aggregate carrying amount of all noncontrolling interests which are redeemable by the (parent) entity (1) at a fixed or determinable price on a fixed or determinable date, (2) at the option of the holder of the noncontrolling interest, or (3) upon occurrence of an event that is not solely within the control of the (parent) entity. This item includes noncontrolling interest holder's ownership (or holders' ownership) regardless of the type of equity interest (common, preferred, other) including all potential organizational (legal) forms of the investee entity.

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