Workforce Reduction Costs - Other Current Liabilities (Details) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Nov. 23, 2014
Restructuring Cost and Reserve [Line Items]
Payments	$ (10.4)
Adjustments	(0.7)
Balance at November 23, 2014	21.0
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	1.5
Employee termination benefits
Restructuring Cost and Reserve [Line Items]
Payments	(9.7)	[1]
Adjustments	(0.4)	[1]
Balance at November 23, 2014	20.5	[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	(0.7)
Adjustments	(0.3)
Balance at November 23, 2014	0.5
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.