Benefit Plans and Other Postretirement Benefits, Net pension expense (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
United States
Weighted average assumptions used to determine net periodic benefit cost/expense:
Rate of compensation increase (as a percent)	3.00%	3.00%	3.00%
Foreign.
Weighted average assumptions used to determine net periodic benefit cost/expense:
Rate of compensation increase (as a percent)	1.70%	1.63%	1.61%
Pension Benefits
Components of net pension expense:
Service cost	$ 7.3	$ 9.6	$ 9.0
Interest cost	19.6	20.0	20.9
Expected return on plan assets	(38.3)	(30.7)	(30.1)
Amortization of prior service cost	2.3	2.7	2.4
Settlements	0.6
Amortization of net actuarial losses	23.2	22.9	22.0
Net pension expense	14.7	24.5	24.2
Pension Benefits | United States
Components of net pension expense:
Service cost	4.5	6.7	6.2
Interest cost	14.9	15.3	15.4
Expected return on plan assets	(34.5)	(27.2)	(26.2)
Amortization of prior service cost	2.3	2.7	2.4
Amortization of net actuarial losses	19.0	18.3	18.6
Net pension expense	$ 6.2	$ 15.8	$ 16.4
Weighted average assumptions used to determine net periodic benefit cost/expense:
Discount rate (as a percent)	3.48%	3.93%	4.11%
Expected long-term return on assets (as a percent)	7.75%	7.75%	7.75%
Pension Benefits | Foreign.
Components of net pension expense:
Service cost	$ 2.8	$ 2.9	$ 2.8
Interest cost	4.7	4.7	5.5
Expected return on plan assets	(3.8)	(3.5)	(3.9)
Settlements	0.6
Amortization of net actuarial losses	4.2	4.6	3.4
Net pension expense	$ 8.5	$ 8.7	$ 7.8
Weighted average assumptions used to determine net periodic benefit cost/expense:
Discount rate (as a percent)	2.21%	2.28%	2.96%
Expected long-term return on assets (as a percent)	3.69%	3.80%	4.29%