Accumulated Other Comprehensive Loss - Summary (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022	Jun. 30, 2023	Jun. 30, 2022
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	$ 54.0	$ (79.6)	$ 21.8	$ (64.4)
Other comprehensive income (loss) before reclassifications			16.2
Amounts reclassified from accumulated other comprehensive loss			217.2
Total other comprehensive income (loss)	30.7	(7.2)	233.4	32.4
Ending balance	49.3	(98.5)	49.3	(98.5)
Total
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance	(2,873.2)	(3,223.3)	(3,076.0)	(3,264.1)
Ending balance	(2,842.6)	$ (3,230.5)	(2,842.6)	$ (3,230.5)
Translation Adjustments
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			(977.4)
Other comprehensive income (loss) before reclassifications			57.5
Amounts reclassified from accumulated other comprehensive loss			(3.4)
Total other comprehensive income (loss)			54.1
Ending balance	(923.3)		(923.3)
Postretirement Plans
AOCI Attributable to Parent, Net of Tax [Roll Forward]
Beginning balance			(2,098.6)
Other comprehensive income (loss) before reclassifications			(41.3)
Amounts reclassified from accumulated other comprehensive loss			220.6
Total other comprehensive income (loss)			179.3
Ending balance	$ (1,919.3)		$ (1,919.3)