Earnings Per Share Earnings per share (non-printing) (Details) - shares shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016
Earnings Per Share [Abstract]
Anti-dilutive shares	0.0	0.2	0.0	0.1