Benefit Plans and Other Postretirement Benefits, Benefit obligation and plan assets (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
	Jan. 31, 2018	Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Amounts recognized in the balance sheet as of December 31:
Accrued pension and postretirement benefit obligations		$ 198.8	$ 190.2
Accumulated other comprehensive loss, net		$ (430.9)	$ (390.2)
United States
Weighted average assumptions used to determine projected benefit obligations:
Rate of compensation increase (as a percent)		2.60%	3.00%
Foreign.
Weighted average assumptions used to determine projected benefit obligations:
Rate of compensation increase (as a percent)		1.78%	1.77%
Pension Benefits
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	$ 741.7	$ 684.2	$ 741.7
Service cost		8.0	7.3	$ 9.6
Interest cost		21.5	19.6	20.0
Plan amendments		4.8	1.0
Actuarial (gain) loss		71.9	(36.2)
Foreign exchange translation		1.6	(13.0)
Benefits paid		(34.1)	(36.2)
Projected benefit obligation at end of year		757.9	684.2	741.7
Change in plan assets:
Fair value of plan assets at the beginning of the year	497.9	514.1	497.9
Actual return on plan assets		91.9	(29.7)
Employer contributions		6.6	88.3	22.5
Foreign exchange translation		2.5	(6.2)
Benefits paid		(34.1)	(36.2)
Fair value of plan assets at end of year		581.0	514.1	497.9
Underfunded status at end of year		176.9	170.1
Amounts recognized in the balance sheet as of December 31:
Other accrued expenses		4.2	3.9
Accrued pension and postretirement benefit obligations		172.7	166.2
Accumulated other comprehensive loss, net		(193.5)	(192.9)
Accumulated benefit obligation
Accumulated benefit obligation		748.4	674.5
Pension Benefits | United States
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	486.7	448.9	486.7
Service cost		5.4	4.5	6.7
Interest cost		16.8	14.9	15.3
Plan amendments		4.8	0.2
Actuarial (gain) loss		47.1	(33.1)
Foreign exchange translation		0.0	0.0
Benefits paid		(26.5)	(24.3)
Projected benefit obligation at end of year		496.5	448.9	486.7
Change in plan assets:
Fair value of plan assets at the beginning of the year	389.6	418.2	389.6
Actual return on plan assets		80.5	(28.8)
Employer contributions	81.0	1.0	81.7
Foreign exchange translation		0.0	0.0
Benefits paid		(26.5)	(24.3)
Fair value of plan assets at end of year		473.2	418.2	389.6
Underfunded status at end of year		23.3	30.7
Amounts recognized in the balance sheet as of December 31:
Other accrued expenses		1.0	1.0
Accrued pension and postretirement benefit obligations		22.3	29.7
Accumulated other comprehensive loss, net		$ (131.5)	$ (140.2)
Weighted average assumptions used to determine projected benefit obligations:
Benefit obligation discount rate (as a percent)		3.11%	4.14%
Increase (decrease) in benefit obligation due to change in discount rate		$ 50.0
Accumulated benefit obligation
Accumulated benefit obligation		495.0	$ 446.4
Pension Benefits | Foreign.
Change in projected benefit obligation:
Projected benefit obligation at beginning of year	255.0	235.3	255.0
Service cost		2.6	2.8	2.9
Interest cost		4.7	4.7	4.7
Plan amendments		0.0	0.8
Actuarial (gain) loss		24.8	(3.1)
Foreign exchange translation		1.6	(13.0)
Benefits paid		(7.6)	(11.9)
Projected benefit obligation at end of year		261.4	235.3	255.0
Change in plan assets:
Fair value of plan assets at the beginning of the year	$ 108.3	95.9	108.3
Actual return on plan assets		11.4	(0.9)
Employer contributions		5.6	6.6
Foreign exchange translation		2.5	(6.2)
Benefits paid		(7.6)	(11.9)
Fair value of plan assets at end of year		107.8	95.9	$ 108.3
Underfunded status at end of year		153.6	139.4
Amounts recognized in the balance sheet as of December 31:
Other accrued expenses		3.2	2.9
Accrued pension and postretirement benefit obligations		150.4	136.5
Accumulated other comprehensive loss, net		$ (62.0)	$ (52.7)
Weighted average assumptions used to determine projected benefit obligations:
Benefit obligation discount rate (as a percent)		1.59%	2.28%
Accumulated benefit obligation
Accumulated benefit obligation		$ 253.4	$ 228.1
Largest foreign pension plan | Pension Benefits | Unfunded Plan | Foreign.
Change in projected benefit obligation:
Projected benefit obligation at beginning of year		92.7
Projected benefit obligation at end of year		$ 103.6	$ 92.7