Restructuring Initiatives (Schedule of restructuring charges classification) (Details) - USD ($) $ in Millions	3 Months Ended
	Aug. 26, 2018	Aug. 27, 2017
Restructuring and Related Cost [Line Items]
Restructuring charges (recoveries)	$ (1.2)	$ 17.5
Project-related costs classified in cost of sales	1.2	1.2
Cost of Sales [Member]
Restructuring and Related Cost [Line Items]
Restructuring charges (recoveries)	0.2	12.3
Restructuring, Impairment, and Other Exit Costs [Member]
Restructuring and Related Cost [Line Items]
Restructuring charges (recoveries)	$ (1.4)	$ 5.2