Segment Information - Schedule of Net Earned Premiums, Fees and Other Income by Segment (Details) - Operating Segments - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Global Lifestyle
Segment Reporting Information [Line Items]
Net earned premiums	$ 1,990.3	$ 1,961.2	$ 5,933.5	$ 5,757.0
Global Lifestyle \| Connected Living
Segment Reporting Information [Line Items]
Net earned premiums	1,046.8	1,094.1	3,182.0	3,221.9
Global Lifestyle \| Global Automotive
Segment Reporting Information [Line Items]
Net earned premiums	943.5	867.1	2,751.5	2,535.1
Global Housing
Segment Reporting Information [Line Items]
Net earned premiums	484.1	471.1	1,465.8	1,447.6
Global Housing \| Lender-placed Insurance
Segment Reporting Information [Line Items]
Net earned premiums	262.2	256.2	801.9	790.9
Global Housing \| Multifamily Housing
Segment Reporting Information [Line Items]
Net earned premiums	119.9	121.7	362.0	361.2
Global Housing \| Specialty and Other
Segment Reporting Information [Line Items]
Net earned premiums	$ 102.0	$ 93.2	$ 301.9	$ 295.5