Restructuring (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020	Dec. 31, 2020
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 0.2	$ (0.1)	$ 6.4	$ 9.5
Deferred taxes on land held for sale	81.3		81.3		$ 42.2
Restructuring Reserve [Roll Forward]
Accrued charges/Balance at beginning of period			8.0
Expenses			6.8
Payments/Deductions			(5.5)
Accrued charges/Balance at end of period	9.3		9.3
Corporate Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	(0.1)	(0.3)		9.0
Cumulative life-to-date charges	25.4		25.4
Transformational Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	0.3		6.4
Cumulative life-to-date charges	6.4		6.4
Other Restructurings
Restructuring Cost and Reserve [Line Items]
Restructuring Charges		0.2		0.5
Accelerated Depreciation | Corporate Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring Charges			(0.4)	2.5
Cumulative life-to-date charges	2.5		2.5
Employee Termination Benefit Charges [Member]
Restructuring Reserve [Roll Forward]
Accrued charges/Balance at beginning of period			7.9
Expenses			6.8
Payments/Deductions			(5.4)
Accrued charges/Balance at end of period	9.3		9.3
Employee Termination Benefit Charges [Member] | Corporate Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	(0.1)	(0.5)	0.4	3.9
Cumulative life-to-date charges	19.9		19.9
Employee Termination Benefit Charges [Member] | Transformational Restructuring Program [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	0.3		6.4
Cumulative life-to-date charges	6.4		6.4
Employee Termination Benefit Charges [Member] | Transformational Restructuring Program [Member] | Maximum [Member]
Restructuring Cost and Reserve [Line Items]
Expected restructuring charges	1.0		1.0
Contract Termination Charges [Member]
Restructuring Reserve [Roll Forward]
Accrued charges/Balance at beginning of period			0.1
Payments/Deductions			(0.1)
Contract Termination Charges [Member] | Corporate Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring Charges				2.4
Cumulative life-to-date charges	2.8		2.8
Other Restructuring | Corporate Restructuring Program
Restructuring Cost and Reserve [Line Items]
Restructuring Charges		$ 0.2		$ 0.2
Cumulative life-to-date charges	$ 0.2		$ 0.2