NONCONTROLLING INTERESTS - Schedule of Noncontrolling Interests (Details) - USD ($) $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024	Jun. 30, 2025	Dec. 31, 2024	Jun. 30, 2024	Dec. 31, 2023
Redeemable Noncontrolling Interest [Line Items]
Redeemable noncontrolling interests	$ 7,469,059		$ 7,469,059			$ 6,977,749
Net income (loss) attributable to redeemable noncontrolling interest	415,200	$ 450,176	548,287	$ 919,734
Variable Interest Entity, Primary Beneficiary
Redeemable Noncontrolling Interest [Line Items]
Redeemable noncontrolling interests	7,469,059		7,469,059			6,977,749
Net income (loss) attributable to redeemable noncontrolling interest	415,200	450,176	548,287	919,734
DaVinciRe Holdings Ltd. \| Variable Interest Entity, Primary Beneficiary
Redeemable Noncontrolling Interest [Line Items]
Redeemable noncontrolling interests	3,454,255	2,958,452	3,454,255	2,958,452	$ 3,210,791	3,061,708	$ 2,760,164	$ 2,541,482
Net income (loss) attributable to redeemable noncontrolling interest	243,464	223,288	349,476	523,812
Medici \| Variable Interest Entity, Primary Beneficiary
Redeemable Noncontrolling Interest [Line Items]
Redeemable noncontrolling interests	1,623,315	1,680,520	1,623,315	1,680,520	1,532,990	1,646,745	1,631,508	1,650,229
Net income (loss) attributable to redeemable noncontrolling interest	79,573	123,497	133,729	183,015
Vermeer \| Variable Interest Entity, Primary Beneficiary
Redeemable Noncontrolling Interest [Line Items]
Redeemable noncontrolling interests	1,821,183	1,738,426	1,821,183	1,738,426	1,750,202	1,799,857	1,489,892	1,555,297
Net income (loss) attributable to redeemable noncontrolling interest	70,981	73,534	21,326	183,129
Fontana \| Variable Interest Entity, Primary Beneficiary
Redeemable Noncontrolling Interest [Line Items]
Redeemable noncontrolling interests	570,306	483,601	570,306	483,601	$ 549,124	$ 469,439	$ 453,744	$ 353,823
Net income (loss) attributable to redeemable noncontrolling interest	$ 21,182	$ 29,857	$ 43,756	$ 29,778