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Amount of operating loss carryforward, before tax effects, available to reduce future taxable income under enacted tax laws.

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Income taxes - other information (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2025	Sep. 30, 2025	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023	Jul. 04, 2025
Additional information about valuation allowance
Increase (decrease)			$ (24.0)	$ 8.0	$ 26.4
Amount	$ 190.1		190.1	214.1
Additional information about uncertain tax positions
Unrecognized tax benefits that would impact effective tax rate	79.1		79.1	31.3	50.8
Accrued interest and penalties	11.1		11.1	$ 7.2	$ 8.2
Impairment loss	785.0	$ 785.0	785.0
Other matters
Undistributed earnings of foreign subsidiaries	2,776.2		2,776.2
Reduction in current cash tax obligations						$ 43.0
Federal
Other matters
Operating loss carryforwards	3.1		3.1
State and Local
Other matters
Operating loss carryforwards	70.8		70.8
Foreign
Other matters
Operating loss carryforwards	560.5		560.5
Foreign net operating loss carryforward
Additional information about valuation allowance
Amount	$ 132.1		$ 132.1