Stockholders' Equity (Schedule of Components of Accumulated Other Comprehensive Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Aug. 26, 2012	Aug. 28, 2011	May 27, 2012	May 29, 2011
Stockholders' Equity Note [Abstract]
Foreign currency translation adjustment	$ (0.8)	$ (0.7)	$ (1.6)	$ (0.4)
Unrealized gains (losses) on marketable securities, net of tax	0.3	0.5	0.4	0.5
Unrealized gains (losses) on derivatives, net of tax	(53.3)	(33.9)	(49.7)	(4.1)
Benefit plan funding position, net of tax	(94.0)	(54.0)	(95.7)	(55.8)
Total accumulated other comprehensive income (loss)	(147.8)	(88.1)	(146.6)	(59.8)
Foreign currency adjustment	0.8	(0.3)
Unrealized Gains (Losses) on Derivatives adjustment	(4.3)	(29.5)
Accumulated Other Comprehensive Income Gain (loss)	(3.6)	(29.8)
Other Comprehensive Income (Loss), Reclassification Adjustment on Derivatives Included in Net Income, Net of Tax	0.7	(0.3)
Other Comprehensive Income (Loss), Reclassification, Benefit Plan Funding Position, Net Gain (Loss) Recognized in Net Periodic Benefit Cost, Net of Tax	1.7	1.8
Other Comprehensive Income (Loss) Net Of Tax Reclassification Realized In Net Earnings	2.4	1.5
Other Comprehensive Income (loss), Unrealized (Gains (Losses) on Marketable Securities adjustment, net of tax	$ (0.1)	$ 0