Defined contribution and defined benefit retirement plans- Schedule of Rollforward of Change in Fair Value of Level 3 Assets (Details) - Pension Plans - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024
Schedule Of Reconciliation Of Changes In Fair Value Of Assets And Liabilities [Line Items]
Fair value at beginning of the year	$ 480.6
Fair value at end of the year	464.9	$ 480.6
Significant unobservable inputs (Level 3)
Schedule Of Reconciliation Of Changes In Fair Value Of Assets And Liabilities [Line Items]
Fair value at beginning of the year	286.0	292.1
Gain on assets held at end of year	13.8	12.8
Gain (loss) on assets sold during the year	(6.7)	(0.7)
Assets purchased	1.6	1.5
Assets sold	(2.0)	(2.3)
Currency exchange rate fluctuations	36.8	(17.4)
Fair value at end of the year	$ 329.5	$ 286.0