Workforce Reduction Costs (Other Current Liabilities) (Details) - USD ($) $ in Millions		3 Months Ended			9 Months Ended
		Feb. 28, 2016		Feb. 22, 2015	Feb. 28, 2016		Feb. 22, 2015
Restructuring Cost and Reserve [Line Items]
Other restructuring costs		$ (0.1)	[1]	$ (0.7)	$ (0.1)	[1]	$ (28.1)
Payments					(35.5)
Adjustments					0.5
Balance at February 28, 2016		4.3			4.3
Fiscal Year 2014 Plans
Restructuring Cost and Reserve [Line Items]
Restructuring charges					14.5
Fiscal Year 2015 Plans
Restructuring Cost and Reserve [Line Items]
Restructuring charges					24.8
Employee termination benefits
Restructuring Cost and Reserve [Line Items]
Other restructuring costs	[2]	0.0	[1]	(0.7)	(0.2)	[1]	(27.7)
Payments	[3]				(34.2)
Adjustments	[3]				0.8
Balance at February 28, 2016	[3]	4.2			4.2
Employee termination benefits | Fiscal Year 2014 Plans
Restructuring Cost and Reserve [Line Items]
Restructuring charges	[3]				13.4
Employee termination benefits | Fiscal Year 2015 Plans
Restructuring Cost and Reserve [Line Items]
Restructuring charges	[3]				24.2
Other
Restructuring Cost and Reserve [Line Items]
Other restructuring costs	[4]	(0.1)	[1]	$ 0.0	(0.1)	[1]	$ (0.4)
Payments					(1.3)
Adjustments					(0.3)
Balance at February 28, 2016		$ 0.1			0.1
Other | Fiscal Year 2014 Plans
Restructuring Cost and Reserve [Line Items]
Restructuring charges					1.1
Other | Fiscal Year 2015 Plans
Restructuring Cost and Reserve [Line Items]
Restructuring charges					$ 0.6

[1] Reflects subsequent adjustments to the fiscal 2014 and 2015 plans based on updated information.

[2] Includes salary and stock-based compensation expense.

[3] Excludes costs associated with stock options and restricted stock that will be settled in shares upon vesting.

[4] Includes postemployment medical, outplacement and relocation costs.