Segment Information - Revenues from exited business (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2022	Sep. 30, 2022
Revenues from exited business:
Change in fair value of funds withheld embedded derivative	$ 1,237.7	$ 4,305.0
Net realized capital gains (losses) on funds withheld assets	8.5	697.5
Reconciling Items
Revenues from exited business:
Change in fair value of funds withheld embedded derivative	1,237.7	4,305.0
Net realized capital gains (losses) on funds withheld assets	8.5	697.5
Strategic review costs and impacts		32.4
Amortization of reinsurance gain	3.4	8.3
Total revenues from exited business	$ 1,249.6	$ 5,043.2