Interim Financial Statements (Details) - USD ($) $ in Millions	9 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2018	Jun. 30, 2020	Mar. 31, 2020	Jan. 01, 2020	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of adopting Topic 326	$ (1,694.4)	$ (1,467.7)	$ (1,197.2)	$ (1,532.2)	$ (1,456.5)		$ (1,359.2)	$ (1,274.7)	$ (1,250.5)
Accounts receivable, net	511.7	505.0				$ 504.5
Allowance for doubtful accounts	6.3	7.3
Other non-current assets	632.8	388.5				382.5
Total Assets	6,395.7	6,083.9				6,077.4
Deferred income taxes	135.7	131.1				129.4
Total Liabilities	4,701.3	4,616.2				4,614.5
Retained earnings	1,658.8	1,401.8				1,397.0
Total Liabilities and Stockholders’ Equity	$ 6,395.7	$ 6,083.9				6,077.4
Accounting Standards Update [Extensible List]	us-gaap:AccountingStandardsUpdate201613Member	us-gaap:AccountingStandardsUpdate201613Member	us-gaap:AccountingStandardsUpdate201602Member
Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of adopting Topic 326		$ 4.8	$ (0.9)
Accounts receivable, net						(0.5)
Other non-current assets						(6.0)
Total Assets						(6.5)
Deferred income taxes						(1.7)
Total Liabilities						(1.7)
Retained earnings						(4.8)
Total Liabilities and Stockholders’ Equity						(6.5)
Retained Earnings
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of adopting Topic 326	$ (1,658.8)	(1,401.8)	(1,162.1)	$ (1,507.1)	$ (1,436.2)		$ (1,340.7)	$ (1,262.5)	$ (1,212.7)
Retained Earnings | Cumulative Effect, Period of Adoption, Adjustment
New Accounting Pronouncements or Change in Accounting Principle [Line Items]
Cumulative effect of adopting Topic 326		$ 4.8	$ (0.9)			$ 4.8