Special Items Restructuring Accruals (Details) $ in Millions		3 Months Ended	12 Months Ended
	Oct. 28, 2019 USD ($) employee	Sep. 30, 2018 employee	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)
Restructuring Cost and Reserve [Line Items]
Special items, net			$ 1,740.2	$ 708.8	$ (249.7)
U.S.
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated | employee		300
Employee Severance
Restructuring Reserve [Roll Forward]
Restructuring accruals, beginning balance			47.1	25.6	6.9
Charges incurred and changes in estimates			73.2	52.4	34.7
Payments made			(88.4)	(31.1)	(15.8)
Changes in estimates			(5.6)
Foreign currency and other adjustments			0.2	0.2	(0.2)
Restructuring accruals, ending balance			26.5	47.1	25.6
Employee Severance | North America [Member]
Restructuring Reserve [Roll Forward]
Restructuring accruals, beginning balance			42.6	24.5	4.9
Charges incurred and changes in estimates			63.7	43.4	31.2
Payments made			(77.3)	(25.5)	(11.5)
Changes in estimates			(4.6)
Foreign currency and other adjustments			0.1	0.2	(0.1)
Restructuring accruals, ending balance			24.5	42.6	24.5
Employee Severance | Europe [Member]
Restructuring Reserve [Roll Forward]
Restructuring accruals, beginning balance			4.5	1.1	2.0
Charges incurred and changes in estimates			9.5	9.0	3.5
Payments made			(11.1)	(5.6)	(4.3)
Changes in estimates			(1.0)
Foreign currency and other adjustments			0.1	0.0	(0.1)
Restructuring accruals, ending balance			2.0	4.5	$ 1.1
Revitalization Restructuring Costs [Member]
Restructuring Reserve [Roll Forward]
Charges incurred and changes in estimates			35.6	41.2
Restructuring accruals, ending balance			19.0
Corporate | Closure of Denver Office [Member]
Restructuring Cost and Reserve [Line Items]
Special items, net			$ 7.6	$ 2.1
Minimum | Revitalization Restructuring Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Cost	$ 100.0
Maximum
Restructuring Cost and Reserve [Line Items]
Payment of Severance Obligations, Term			12 months
Maximum | Revitalization Restructuring Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Number of Positions Eliminated | employee	600
Restructuring and Related Cost, Expected Cost	$ 120.0