Equity (Reconciliation of Ordinary Shares) (Details) - USD ($) shares in Millions, $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Increase (Decrease) In Ordinary Shares [Roll Forward]
Treasury Stock, Shares, Acquired	(0.8)
Treasury Stock, Value, Acquired, Cost Method	$ (60.0)	$ (30.0)
Common Stock [Member]
Increase (Decrease) In Ordinary Shares [Roll Forward]
December 31, 2016	95.3
Shares issued under incentive plans, net	0.5
Treasury Stock, Shares, Acquired	(0.8)
September 30, 2017	95.0