Assets and Liabilities Held for Sale and Discontinued Operations - Additional Disclosures (Details) (USD $) In Millions, unless otherwise specified	0 Months Ended	1 Months Ended	3 Months Ended			6 Months Ended			3 Months Ended		4 Months Ended	6 Months Ended					0 Months Ended
	Apr. 14, 2014	Apr. 30, 2014 letter	Jun. 14, 2014	Mar. 22, 2014	Jun. 15, 2013	Jun. 14, 2014 plan	Jun. 15, 2013	Dec. 28, 2013	Jun. 14, 2014 Dominick's Stores [Member]	Jun. 15, 2013 Dominick's Stores [Member]	Dec. 28, 2013 Dominick's Stores [Member] plan	Jun. 14, 2014 Dominick's Stores [Member]	Jun. 15, 2013 Dominick's Stores [Member]	Jun. 14, 2014 Minimum [Member]	Jun. 14, 2014 Maximum [Member]	Mar. 24, 2014 Blackhawk Network Holdings, Inc. [Member]	Apr. 14, 2014 Common Class B [Member] Blackhawk Network Holdings, Inc. [Member]	Mar. 24, 2014 Common Class B [Member] Blackhawk Network Holdings, Inc. [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Subsidiary shares owned																		37.8
Percent of total outstanding shares of Blackhawk Class B common stock owned																		94.20%
Percent of total outstanding shares of Blackhawk common stock, all classes, owned																72.00%
Common stock dividend, share of Blackhawk Class B received																	0.164291
Expected tax from distribution of Blackhawk shares	$ 360
Cash proceeds from sale of stores											72.2	107.5
Pre-tax gain (loss) from sale of stores			7.8		0	44.9	0		13.5	0	(493.1)	55.6	0
Multi-employer pension plan withdrawal liability			348.8			348.8		310.8
Number of multiemployer pension plans											4
Demand letters received		2
Increase in multi-employer pension plan withdrawal liability				33.8
Reduction in earnings from discontinued operations from increase in multi-employer pension plan withdrawal liability, net of tax				21.1
Multiemployer pension plan, withdrawal obligation annual installment														$ 10	$ 20
Multiemployer pension plan, withdrawal obligation payment period						20 years
Number of multiemployer pension plans that may send demand letters in 2014 or later						2