Earnings Per Share (Details) - USD ($) $ / shares in Units, $ in Millions	3 Months Ended		6 Months Ended
	Aug. 28, 2020	Aug. 23, 2019	Aug. 28, 2020	Aug. 23, 2019	May 29, 2020	Feb. 28, 2020	May 24, 2019	Feb. 22, 2019
Earnings Per Share [Abstract]
Net income	$ 55.5	$ 60.5	$ 17.4	$ 78.3
Adjustment for earnings attributable to participating securities	(1.3)	(1.3)	(0.4)	(1.5)
Net income used in calculating earnings per share	$ 54.2	$ 59.2	$ 17.0	$ 76.8
Weighted-average common shares outstanding including participating securities (in millions)	117,600,000	119,700,000	117,400,000	119,600,000
Adjustment for participating securities (in millions)	(2,800,000)	(2,400,000)	(2,400,000)	(2,300,000)
Shares used in calculating basic earnings per share (in millions)	114,800,000	117,300,000	115,000,000.0	117,300,000
Effect of dilutive stock-based compensation (in millions)	200,000	500,000	200,000	500,000
Shares used in calculating diluted earnings per share (in millions)	115,000,000.0	117,800,000	115,200,000	117,800,000
Earnings per share, basic	$ 0.47	$ 0.50	$ 0.15	$ 0.65
Earnings per share, diluted	$ 0.47	$ 0.50	$ 0.15	$ 0.65
Common Stock, Shares, Outstanding	114,776,546	117,243,960	114,776,546	117,243,960	114,759,549	117,202,000	117,313,755	116,766,610
Anti-dilutive performance units excluded from computation of diluted earnings per share (in millions)	0	0	0	0