Accumulated Other Comprehensive Loss - Summary (Details) $ in Millions	3 Months Ended
	Mar. 31, 2024 USD ($)
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ (151.8)
Other comprehensive (loss) income before reclassifications	(8.2)
Amounts reclassified from accumulated other comprehensive loss	146.5
Current period other comprehensive income (loss)	138.3
Ending balance	(158.6)
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(2,800.3)
Ending balance	(2,662.0)
Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(912.8)
Other comprehensive (loss) income before reclassifications	(15.2)
Amounts reclassified from accumulated other comprehensive loss	0.5
Current period other comprehensive income (loss)	(14.7)
Ending balance	(927.5)
Postretirement Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(1,887.5)
Other comprehensive (loss) income before reclassifications	7.0
Amounts reclassified from accumulated other comprehensive loss	146.0
Current period other comprehensive income (loss)	153.0
Ending balance	$ (1,734.5)