Benefit Plans (Components of Net Periodic Benefit Cost) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Net periodic benefit cost:
Curtailment	$ 2.1	$ 0.0	$ 0.0
Settlement effects	0.0	50.4	0.0
Other changes in plan assets and benefit obligations recognized in OCI, pre-tax:
Foreign currency translation	0.0	0.0	0.0
Pension Benefits [Member]
Net periodic benefit cost:
Service cost	10.2	10.6	9.8
Interest cost	10.5	13.8	17.1
Expected return on assets	(12.6)	(19.5)	(19.3)
Amortization of prior service (credit) cost	(1.4)	(1.3)	(1.3)
Amortization of transition obligation	0.1	0.1	0.1
Amortization of actuarial loss (gain)	4.8	5.9	4.7
Curtailment	2.1	0.0	0.0
Settlement effects	0.0	50.4	0.0
Net periodic benefit cost	9.5	60.0	11.1
Other changes in plan assets and benefit obligations recognized in OCI, pre-tax:
Net loss (gain) arising during period	19.2	17.7	31.5
Prior service credit arising during period	0.0	(0.7)	0.0
Amortization of prior service credit	1.4	1.3	1.3
Amortization of transition obligation	(0.1)	(0.1)	(0.1)
Amortization of actuarial (loss) gain	(4.8)	(5.9)	(4.7)
Curtailment	3.1	50.4
Settlement effects	0.0		0.0
Foreign currency exchange rate effects on the above items	(3.2)	(1.6)	(2.1)
Foreign currency translation	(4.5)	(1.7)
Total recognized in OCI	9.4	(39.7)	25.9
Total recognized in net periodic benefit cost and OCI	18.9	20.3	37.0
U.S. Pension Plans [Member]
Net periodic benefit cost:
Net periodic benefit cost	7.1	57.4	8.1
International Pension Plan [Member]
Net periodic benefit cost:
Net periodic benefit cost	2.4	2.6	3.0
Other Retirement Benefits [Member]
Net periodic benefit cost:
Service cost	0.5	0.5	0.4
Interest cost	0.5	0.4	0.4
Expected return on assets	0.0	0.0	0.0
Amortization of prior service (credit) cost	0.0	0.0	0.0
Amortization of transition obligation	0.0	0.0	0.0
Amortization of actuarial loss (gain)	(1.4)	(1.4)	(1.6)
Curtailment	0.0	0.0	0.0
Settlement effects	0.0	0.0	0.0
Net periodic benefit cost	(0.4)	(0.5)	(0.8)
Other changes in plan assets and benefit obligations recognized in OCI, pre-tax:
Net loss (gain) arising during period	(0.1)	(0.8)	0.1
Prior service credit arising during period	(3.0)	0.0	0.0
Amortization of prior service credit	0.0	0.0	0.0
Amortization of transition obligation	0.0	0.0	0.0
Amortization of actuarial (loss) gain	1.4	1.4	1.6
Settlement effects	0.0	0.0	0.0
Foreign currency translation	0.0	0.0
Total recognized in OCI	(1.7)	0.6	1.7
Total recognized in net periodic benefit cost and OCI	(2.1)	0.1	0.9
U.S. Defined Benefit Plans [Member]
Net periodic benefit cost:
Net periodic benefit cost	(0.4)	(0.5)	(0.8)
International Defined Benefit Plans [Member]
Net periodic benefit cost:
Net periodic benefit cost	$ 0.0	$ 0.0	$ 0.0