Stockholders' Equity (Schedule of Components of Accumulated Other Comprehensive Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Aug. 24, 2014	Aug. 25, 2013
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	$ (128.1)	$ (132.8)
Gain (loss)	(3.3)	(5.5)
Reclassification realized in net earnings	28.9	3.9
Ending Balance	(102.5)	(134.4)
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	(4.7)	(1.8)
Gain (loss)	(1.2)	(1.0)
Reclassification realized in net earnings	2.7	0
Ending Balance	(3.2)	(2.8)
Unrealized Gains (Losses) on Marketable Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	0.1	0.2
Gain (loss)	(0.1)	(0.1)
Reclassification realized in net earnings	0	0
Ending Balance	0	0.1
Unrealized Gains (Losses) on Derivatives
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	(50.4)	(53.8)
Gain (loss)	(2.0)	(4.4)
Reclassification realized in net earnings	25.9	2.3
Ending Balance	(26.5)	(55.9)
Benefit Plan Funding Position
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	(73.1)	(77.4)
Gain (loss)	0	0
Reclassification realized in net earnings	0.3	1.6
Ending Balance	$ (72.8)	$ (75.8)