Earnings Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended								12 Months Ended
	Feb. 22, 2019	Nov. 23, 2018	Aug. 24, 2018	May 25, 2018	Feb. 23, 2018	Nov. 24, 2017	Aug. 25, 2017	May 26, 2017	Feb. 22, 2019	Feb. 23, 2018	Feb. 24, 2017
Earnings Per Share [Abstract]
Net income	$ 22.6	$ 37.3	$ 49.1	$ 17.0	$ 0.0	$ 25.7	$ 36.9	$ 18.1	$ 126.0	$ 80.7	$ 124.6
Undistributed Earnings (Loss) Allocated to Participating Securities, Basic									(2.5)	(1.5)	(2.4)
Net income used in calculating earnings per share									$ 123.5	$ 79.2	$ 122.2
Weighted-average common shares outstanding including participating securities (in millions)									119.1	119.2	120.7
Adjustment for participating securities (in millions)									(2.4)	(2.3)	(2.3)
Shares used in calculating basic earnings per share (in millions)									116.7	116.9	118.4
Effect of dilutive stock-based compensation (in millions)									0.4	0.2	0.5
Shares used in calculating diluted earnings per share (in millions)									117.1	117.1	118.9
Earnings per share, basic	$ 0.19	$ 0.31	$ 0.41	$ 0.14	$ 0.00	$ 0.22	$ 0.31	$ 0.15	$ 1.06	$ 0.68	$ 1.03
Earnings per share, diluted	$ 0.19	$ 0.31	$ 0.41	$ 0.14	$ 0.00	$ 0.22	$ 0.31	$ 0.15	$ 1.05	$ 0.68	$ 1.03
Total common shares outstanding at period end (in millions)	116.8				116.2				116.8	116.2	117.3
Antidilutive Securities Excluded from Computation of Earnings Per Share, Amount									0.2	0.5	0.3