Asset Impairment, Restructuring and Other Special Charges - Total Charges Related to Asset Impairment, Restructuring and Other Special Charges (Details) - USD ($) $ in Millions	3 Months Ended		12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Restructuring charges
Severance and other costs			$ 155.0	$ 8.2	$ 15.5
Facility exit costs			(2.7)	0.0	5.7
Transaction and integration costs			423.8	144.7	26.5
Non-cash and other items
Asset impairment			17.5	15.4	81.9
Asset write-down			19.1	17.2	0.0
Gain on sale of fixed assets			(3.8)	0.0	(0.8)
Settlements and other			14.8	0.0	0.0
Total expense	$ 167.3	$ 51.6	$ 623.7	185.5	$ 128.8
Property, plant and equipment classified as held for sale		$ 11.2		$ 11.2