Deferred Costs (Details) (USD $)	Aug. 26, 2011	Feb. 28, 2011	Aug. 27, 2010
Deferred costs and future payment commitments for retail supply agreements
Prepaid expenses and other	$ 75,016,000	$ 88,352,000	$ 73,624,000
Other assets	316,099,000	327,311,000	295,902,000
Deferred cost assets	391,115,000	415,663,000	369,526,000
Other current liabilities	(63,846,000)	(64,116,000)	(53,802,000)
Other liabilities	(68,323,000)	(76,301,000)	(55,405,000)
Deferred cost liabilities	(132,169,000)	(140,417,000)	(109,207,000)
Net deferred costs	258,946,000	275,246,000	260,319,000
Deferred Costs (Textuals) [Abstract]
Allowance for deferred costs related to supply	$ 10,300,000	$ 10,700,000	$ 11,600,000