Commitments and Contingencies (Details) - Sirius Group - Swedish Tax Authority - Sirius Group - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Loss Contingencies [Line Items]
Contingent liability	$ 15.5		$ 16.5
Change in contingent liability	$ (1.0)	$ (0.7)

Amount of increase (decrease) in loss contingency liability.

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 450
-SubTopic 20
-Section 50
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=118942415&loc=d3e14326-108349

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	na
Period Type:	duration