Retirement Benefit Plans - Change in Plan Assets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015
Change in plan assets:
Return on plan assets	$ 14.8	$ 10.8
Pension Plan, Defined Benefit [Member]
Change in plan assets:
Fair value of plan assets at beginning of year	553.7	1,772.4
Actual return on plan assets	33.8	23.0
Return on plan assets	4.6	4.4
International plan exchange rate change	0.0	0.0
Defined Benefit Plan, Business Combinations and Acquisitions, Plan Assets	0.0	17.6
Defined Benefit Plan, Settlements, Plan Assets	0.0	(1,162.8)
Benefits paid	(62.5)	(100.9)
Fair value of plan assets at end of year	529.6	553.7
Funded status at end of year	(82.8)	(36.2)
International Plans [Member]
Change in plan assets:
Fair value of plan assets at beginning of year	304.6	349.4
Actual return on plan assets	43.2	4.5
Return on plan assets	10.4	6.4
International plan exchange rate change	(45.4)	(23.6)
Defined Benefit Plan, Business Combinations and Acquisitions, Plan Assets	0.0	0.0
Defined Benefit Plan, Settlements, Plan Assets	0.0	(14.5)
Benefits paid	(44.1)	(17.6)
Fair value of plan assets at end of year	268.7	304.6
Funded status at end of year	$ (45.5)	$ (33.5)