Condensed Consolidated Statements of Comprehensive Income (Loss) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Statement of Comprehensive Income [Abstract]
Net income (loss)	$ (1.0)	$ 29.8
Other comprehensive income (loss):
Foreign currency translation adjustments	4.1	(0.9)
Reclassification adjustment for foreign currency translation included in net income	27.3	0.0
Unrealized losses on fixed maturity securities:
Losses arising during the year	(172.0)	(62.1)
Reclassification adjustment for losses (gains) included in net income	(5.4)	(4.0)
Other comprehensive income (loss) before tax	(146.0)	(67.0)
Unrealized gains (losses) on fixed maturity securities:
Losses arising during the year	(32.8)	(11.8)
Reclassification adjustment for (gains) losses included in net income	(1.0)	(0.8)
Income tax (benefit) provision related to other comprehensive income (loss)	(33.8)	(12.6)
Other comprehensive loss, net of tax	(112.2)	(54.4)
Comprehensive loss	$ (113.2)	$ (24.6)