Long-Term Debt (Narrative) (Details) (USD $)	3 Months Ended
	Aug. 28, 2011 adjustments
Expiration date of credit facility	September 20, 2012
Remaining credit available	$ 348,600,000
Adjustments made to interest rates on funds borrowed	0
Minimum [Member]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.07%
Potential additional utilitzation fee	0.05%
Maximum [Member]
Line of Credit Facility, Unused Capacity, Commitment Fee Percentage	0.175%
Potential additional utilitzation fee	0.15%
Maximum [Member] | New Senior Notes [Member]
Maximum range of interest rate adjustment on funds borrowed	2.00%
Revolving Credit Facility [Member]
Maximum borrowing available under the credit facility	750,000,000
Total debt to total capitalization ratio	0.75
Maximum aggregate borrowings available	1,000,000,000
Increase in credit facility	250,000,000
Base interest rate percentage of revolving credit facility in addition to federal funds rate	0.50%
Applicable interest rate assuming a BBB equivalent credit rating level	0.35%
Maximum amount of borrowings resulting in fluctuation of LIBOR or base rate	100,000,000
Minimum percentage of outstanding amounts on aggregate commitments resulting in decrease of facility fee percentage	50.00%
Amount outstanding under credit facility	0.0
Commercial Paper [Member]
Amount outstanding under credit facility	330,500,000
Letters of Credit [Member]
Amount outstanding under credit facility	70,900,000
Sub Limit [Member]
Maximum aggregate borrowings available	150,000,000
New Senior Notes [Member] | 5.625% Senior Notes Due October 2012 [Member]
Face amount of debt	350,000,000
Interest rate of debt	5.625%
Maturity date of debt	Oct. 01, 2012
New Senior Notes [Member] | 6.200 Percent Senior Notes Due October 2017 [Member]
Face amount of debt	500,000,000
Interest rate of debt	6.20%
Maturity date of debt	Oct. 01, 2017
New Senior Notes [Member] | 6.800% Senior Notes Due October 2037 [Member]
Face amount of debt	$ 300,000,000
Interest rate of debt	6.80%
Maturity date of debt	Oct. 01, 2037