Net Income (Loss) Per Common Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 27, 2020	Jun. 29, 2019	Jun. 27, 2020	Jun. 29, 2019
Net Income (Loss) Per Common Share
Net income (loss) available to common shareholders	$ 79.7	$ 143.4	$ 213.9	$ (3.5)
Weighted average number of common shares outstanding	83.4	84.3	83.4	84.3
Dilutive shares (additional common shares issuable under stock-based awards)	0.4	0.8	0.5
Weighted average number of common shares outstanding, assuming dilution	83.8	85.1	83.9	84.3
Net income (loss) per common share (in dollars per share)	$ 0.96	$ 1.70	$ 2.56	$ (0.04)
Net income (loss) per common share, assuming dilution (in dollars per share)	$ 0.95	$ 1.69	$ 2.55	$ (0.04)
Antidilutive shares, share-based compensation awards				1.0