Special Items Restructuring Accruals (Details) $ in Millions		3 Months Ended		12 Months Ended
	Oct. 28, 2019 USD ($) employee	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($) employee	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)
Restructuring Cost and Reserve [Line Items]
Special items, net				$ 708.8	$ (249.7)	$ 36.4
Operating Lease, Impairment Loss		$ 1.1
Restructuring Reserve [Roll Forward]
Restructuring accruals, beginning balance				25.6	6.9	14.7
Charges incurred and changes in estimates				52.4	34.7	2.6
Payments made				(31.1)	(15.8)	(10.9)
Foreign currency and other adjustments				0.2	(0.2)	0.5
Restructuring accruals, ending balance		47.1	$ 25.6	47.1	25.6	6.9
Revitalization Restructuring Costs [Member]
Restructuring Reserve [Roll Forward]
Charges incurred and changes in estimates				41.2
Restructuring accruals, ending balance		40.0		40.0
U.S.
Restructuring Cost and Reserve [Line Items]
Number of positions eliminated | employee			300
Restructuring Reserve [Roll Forward]
Restructuring accruals, beginning balance				21.6	0.6	5.1
Charges incurred and changes in estimates				18.3	29.6	0.8
Payments made				(23.3)	(8.6)	(5.3)
Foreign currency and other adjustments				0.0	0.0	0.0
Restructuring accruals, ending balance		16.6	$ 21.6	16.6	21.6	0.6
Canada
Restructuring Reserve [Roll Forward]
Restructuring accruals, beginning balance				1.5	4.3	5.9
Charges incurred and changes in estimates				10.4	(0.7)	0.0
Payments made				(0.6)	(2.0)	(1.9)
Foreign currency and other adjustments				0.2	(0.1)	0.3
Restructuring accruals, ending balance		11.5	1.5	11.5	1.5	4.3
Europe [Member]
Restructuring Reserve [Roll Forward]
Restructuring accruals, beginning balance				0.6	1.8	2.8
Charges incurred and changes in estimates				9.0	2.2	0.1
Payments made				(5.1)	(3.3)	(1.3)
Foreign currency and other adjustments				0.0	(0.1)	0.2
Restructuring accruals, ending balance		4.5	0.6	4.5	0.6	1.8
International
Restructuring Reserve [Roll Forward]
Restructuring accruals, beginning balance				0.6	0.2	0.2
Charges incurred and changes in estimates				2.5	2.2	1.6
Payments made				(0.7)	(1.8)	(1.6)
Foreign currency and other adjustments				0.0	0.0	0.0
Restructuring accruals, ending balance		2.4	0.6	2.4	0.6	0.2
Corporate
Restructuring Reserve [Roll Forward]
Restructuring accruals, beginning balance				1.3	0.0	0.7
Charges incurred and changes in estimates				12.2	1.4	0.1
Payments made				(1.4)	(0.1)	(0.8)
Foreign currency and other adjustments				0.0	0.0	0.0
Restructuring accruals, ending balance		$ 12.1	$ 1.3	12.1	$ 1.3	$ 0.0
Corporate | Closure of Denver Office [Member]
Restructuring Cost and Reserve [Line Items]
Special items, net				2.1
Operating Lease, Impairment Loss				$ 1.1
Minimum | Revitalization Restructuring Costs [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring and Related Cost, Expected Number of Positions Eliminated | employee	500
Restructuring and Related Cost, Expected Cost	$ 120.0
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	$ 180.0