Earnings Per Share (EPS) (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]
Weighted-average number of basic shares (in shares)	89.7	92.3	90.1	92.4
Shares issuable under share-based compensation plans (in shares)	0.6	0.4	0.6	0.5
Weighted-average number of diluted shares (in shares)	90.3	92.7	90.7	92.9