Earnings Per Share Components of Basic and Diluted Shares Used In EPS Calculation (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
Weighted-average basic common shares outstanding	240.7	239.6	240.5	215.7
Potential number of shares issuable upon exercise of in-the-money stock options under the Long-term Stock Incentive Plan	0.0	0.0	0.0	0.0
Average diluted common shares outstanding	240.7	239.6	240.5	215.7