Weighted Average Shares Outstanding (Schedule of Weighted Average Shares Outstanding) (Details) - shares shares in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Earnings Per Share [Abstract]
Basic shares outstanding (in shares)	105.4	104.7	105.2	104.5
Effect of potential common stock:
Common stock awards (in shares)	1.3	1.2	1.2	1.1
Diluted shares outstanding (in shares)	106.7	105.9	106.4	105.6