Stockholders' Equity (Schedule of Components of Accumulated Other Comprehensive Income) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Feb. 22, 2015	Feb. 23, 2014	Feb. 22, 2015	Feb. 23, 2014
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	$ (79.8)	$ (127.9)	$ (128.1)	$ (132.8)
Gain (loss)	(0.6)	(2.8)	12.9	(5.3)
Reclassification realized in net earnings	2.6	2.7	37.4	10.1
Ending Balance	(77.8)	(128.0)	(77.8)	(128.0)
Foreign Currency Translation Adjustment
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	0.8	(3.7)	(4.7)	(1.8)
Gain (loss)	(2.0)	(1.7)	(3.8)	(3.6)
Reclassification realized in net earnings	0	0	7.3	0
Ending Balance	(1.2)	(5.4)	(1.2)	(5.4)
Unrealized Gains (Losses) on Marketable Securities
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	0.1	0.1	0.1	0.2
Gain (loss)	0	0	0	(0.1)
Reclassification realized in net earnings	0	0	0	0
Ending Balance	0.1	0.1	0.1	0.1
Unrealized Gains (Losses) on Derivatives
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	(23.0)	(50.1)	(50.4)	(53.8)
Gain (loss)	1.4	(1.1)	2.1	(1.6)
Reclassification realized in net earnings	1.6	1.1	28.3	5.3
Ending Balance	(20.0)	(50.1)	(20.0)	(50.1)
Benefit Plan Funding Position
Accumulated Other Comprehensive Income (Loss), Net of Tax [Roll Forward]
Beginning Balance	(57.7)	(74.2)	(73.1)	(77.4)
Gain (loss)	0	0	14.6	0
Reclassification realized in net earnings	1.0	1.6	1.8	4.8
Ending Balance	$ (56.7)	$ (72.6)	$ (56.7)	$ (72.6)