Pension and Postretirement Benefits - Additional Information (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended	6 Months Ended
	Nov. 25, 2012	Nov. 25, 2012
Pension Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions to pension plan and other postretirement plan	$ 6.3	$ 10.1
Further contribution to pension and other postretirement plan	11.0	11.0
Postretirement Benefits [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Employer contributions to pension plan and other postretirement plan	6.4	13.1
Further contribution to pension and other postretirement plan	$ 10.5	$ 10.5