Amount after tax of gain (loss) not previously recognized resulting from the disposal of a discontinued operation.

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Commitments and Contingencies (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Sep. 30, 2021	Mar. 31, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Loss Contingencies [Line Items]
Net gain from sale of discontinued operations, net of tax	$ 0.0		$ (0.7)	$ 18.7	$ (0.8)
Sirius Group \| Discontinued Operations
Loss Contingencies [Line Items]
Net gain from sale of discontinued operations, net of tax		$ 17.6