Condensed Consolidated Statements of Income (Loss) (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Revenues
Net premiums earned	$ 512.1	$ 141.7	$ 1,234.4	$ 428.9
Net realized and unrealized investment gains (losses)	(11.7)	7.0	43.7	54.6
Net investment income from investments in related party investment funds	202.4	110.6	401.2	8.3
Other net investment income	9.1	4.4	18.8	11.2
Net investment income	199.8	122.0	463.7	74.1
Other revenues	20.7	0.0	47.1	0.0
Total revenues	732.6	263.7	1,745.2	503.0
Expenses
Loss and loss adjustment expenses incurred, net	581.7	110.5	984.9	287.4
Acquisition costs, net	106.9	54.8	281.5	147.7
Other underwriting expenses	89.3	6.1	191.8	21.1
Net corporate and other expenses	19.5	14.9	113.5	30.2
Intangible asset amortization	2.0	0.0	4.1	0.0
Interest expense	9.7	2.1	24.4	6.2
Foreign exchange (gains) losses	(16.1)	5.9	(16.5)	(3.1)
Total expenses	793.0	194.3	1,583.7	489.5
Income (loss) before income tax (expense) benefit	(60.4)	69.4	161.5	13.5
Income tax (expense) benefit	13.0	(0.7)	(6.4)	(4.4)
Net income (loss)	(47.4)	68.7	155.1	9.1
Net loss attributable to noncontrolling interests	3.4	0.0	1.8	0.0
Net income (loss) available to SiriusPoint	(44.0)	68.7	156.9	9.1
Dividends on Series B preference shares	(4.0)	0.0	(9.5)	0.0
Net income (loss) available to SiriusPoint common shareholders	(48.0)	68.7	147.4	9.1
Net income (loss) available to SiriusPoint common shareholders	$ (48.0)	$ 68.7	$ 147.4	$ 9.1
Earnings (loss) per share available to SiriusPoint common shareholders
Basic earnings (loss) per share available to SiriusPoint common shareholders (in dollars per share)	$ (0.30)	$ 0.74	$ 0.94	$ 0.10
Diluted earnings (loss) per share available to SiriusPoint common shareholders (in dollars per share)	$ (0.34)	$ 0.73	$ 0.92	$ 0.10
Weighted average number of common shares used in the determination of earnings (loss) per share
Basic (in shares)	159,225,772	92,613,393	145,095,270	92,466,813
Diluted (in shares)	160,240,888	92,969,646	147,597,964	92,877,674