Workforce Reduction Costs - Other Current Liabilities (Details) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Feb. 22, 2015
Restructuring Cost and Reserve [Line Items]
Payments	$ (18.4)
Adjustments	0.2
Balance at February 22, 2015	13.9
September 2013 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	8.5
January 2014 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	0.8
May 2014 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	5.2
November 2014 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	17.6
Additional restructuring charges	0.5
Employee termination benefits
Restructuring Cost and Reserve [Line Items]
Payments	(17.3)	[1]
Adjustments	0.4	[1]
Balance at February 22, 2015	13.7	[1]
Employee termination benefits | September 2013 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	7.7	[1]
Employee termination benefits | January 2014 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	0.7	[1]
Employee termination benefits | May 2014 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	5.0	[1]
Employee termination benefits | November 2014 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	17.2	[1]
Other
Restructuring Cost and Reserve [Line Items]
Payments	(1.1)
Adjustments	(0.2)
Balance at February 22, 2015	0.2
Other | September 2013 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	0.8
Other | January 2014 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	0.1
Other | May 2014 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	0.2
Other | November 2014 Plan
Restructuring Cost and Reserve [Line Items]
Restructuring Charges	$ 0.4

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