Retirement and Other Benefit Programs (Summary of Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016
Pensions | US
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 14.6	$ 13.0
Interest cost	15.6	11.1
Expected return on plan assets	(15.9)	(8.9)
Curtailment and other	0.0	(69.4)
Net periodic benefit cost	14.3	(54.2)
Pensions | International
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	39.4	18.6
Interest cost	4.9	3.2
Expected return on plan assets	(7.4)	(3.9)
Curtailment and other	1.9	20.0
Net periodic benefit cost	38.8	37.9
OPEB | US
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	1.5	0.8
Interest cost	1.0	0.6
Expected return on plan assets	0.0	0.0
Curtailment and other	0.0	0.0
Net periodic benefit cost	$ 2.5	$ 1.4