Discontinued Operations (Details) (Genuardi Stores [Member], USD $) In Millions, unless otherwise specified	3 Months Ended	12 Months Ended
	Mar. 24, 2012 stores	Dec. 29, 2012
Genuardi Stores [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Number of stores closed	3
Impairment charge of long lived assets and lease exit costs, before tax	$ 14.2
Impairment charge of long lived assets and lease exit costs	8.6
Net cash proceeds from discontinued operations		107.0
Gain on sale of property		52.4
Gain (loss) from discontinured operations, net of tax		$ 31.9