Condensed Consolidated Statements of Comprehensive (Loss) Income - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019
Statement of Comprehensive Income [Abstract]
Net (loss) income	$ (18.8)	$ 91.2
Other comprehensive income (loss):
Foreign currency translation adjustments	(3.4)	0.2
Unrealized (losses) gains on securities:
(Losses) gains arising during the year	(122.8)	56.8
Reclassification adjustment for (gains) losses included in net income	(3.4)	3.1
Other comprehensive (loss) income before tax	(129.6)	60.1
Income tax provision related to other comprehensive income:
(Losses) gain arising during the year	(21.1)	9.1
Reclassification adjustment for losses (gains) included in net income	1.9	0.5
Income tax (benefit) provision related to other comprehensive income	(19.2)	9.6
Other comprehensive (loss) income, net of tax	(110.4)	50.5
Comprehensive (loss) income	$ (129.2)	$ 141.7

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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