Equity (Reconciliation of Ordinary Shares) (Details) shares in Millions	9 Months Ended
	Sep. 30, 2017 shares
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Repurchase of ordinary shares	(10.6)
Common Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	271.7
Shares issued under incentive plans, net	2.1
Repurchase of ordinary shares	0.0
Ending balance	273.8
Treasury Stock [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance	12.7
Shares issued under incentive plans, net	0.0
Ending balance	23.3