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Held for Sale and Discontinued Operations - Narrative (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended		12 Months Ended
	Jun. 30, 2022	Jun. 30, 2021	Jun. 30, 2022	Jun. 30, 2021	Dec. 31, 2018	Dec. 31, 2021	Dec. 31, 2020
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) from sale of Sirius Group, net of tax	$ 0.0	$ 0.0	$ 0.0	$ 18.7
Other Operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Liability related to sale	504.4		504.4			$ 495.3
Assets held for sale - Other	$ 0.0		$ 0.0			$ 16.1
Sirius Group
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) from sale of Sirius Group, net of tax					$ 17.3
Discontinued Operations, Disposed of by Sale \| Sirius Group
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) from sale of Sirius Group, net of tax				17.6
Liability related to sale							$ 18.7
Foreign Currency Gain (Loss) \| Discontinued Operations, Disposed of by Sale \| Sirius Group
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Gain (loss) from sale of Sirius Group, net of tax				$ 1.1