Reserves - Narrative (Details) - USD ($) $ in Millions	6 Months Ended
Reserves - Narrative (Details) - USD ($) $ in Millions	Jun. 30, 2026	Jun. 30, 2025
Liability for Claims and Claims Adjustment Expense [Line Items]
Unfavorable (favorable) prior year development	$ (74.1)	$ (99.3)
Other Product and Services
Liability for Claims and Claims Adjustment Expense [Line Items]
Unfavorable (favorable) prior year development	(5.2)	0.3
Global Lifestyle
Liability for Claims and Claims Adjustment Expense [Line Items]
Unfavorable (favorable) prior year development	(37.9)	(36.8)
Global Lifestyle \| Global Automotive
Liability for Claims and Claims Adjustment Expense [Line Items]
Unfavorable (favorable) prior year development	(20.6)
Global Lifestyle \| Connected Living
Liability for Claims and Claims Adjustment Expense [Line Items]
Unfavorable (favorable) prior year development	(17.3)
Global Lifestyle \| Mobile Contracts
Liability for Claims and Claims Adjustment Expense [Line Items]
Unfavorable (favorable) prior year development	(8.7)
Global Lifestyle \| Extended Service Contracts
Liability for Claims and Claims Adjustment Expense [Line Items]
Unfavorable (favorable) prior year development	(7.1)
Global Lifestyle \| Credit and Other Insurance
Liability for Claims and Claims Adjustment Expense [Line Items]
Unfavorable (favorable) prior year development	(1.5)
Global Housing
Liability for Claims and Claims Adjustment Expense [Line Items]
Unfavorable (favorable) prior year development	(31.0)	(62.8)
Global Housing \| Non-catastrophe Losses
Liability for Claims and Claims Adjustment Expense [Line Items]
Unfavorable (favorable) prior year development	(41.9)	$ 10.9
Global Housing \| Lender-placed Insurance \| Non-catastrophe Losses
Liability for Claims and Claims Adjustment Expense [Line Items]
Unfavorable (favorable) prior year development	$ (29.8)