Earnings Per Share (EPS) (Details) - shares shares in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2018	Jun. 30, 2017
Earnings Per Share [Abstract]
Weighted-average number of basic shares	95.0	95.2	95.1	95.3
Shares issuable under incentive stock plans	0.6	0.7	0.6	0.7
Weighted average number of diluted shares	95.6	95.9	95.7	96.0