Fair Value Measurements (Narrative) (Details) (Fair Value, Measurements, Nonrecurring [Member], USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 15, 2013	Jun. 16, 2012	Jun. 15, 2013	Jun. 16, 2012
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Carrying value of long-lived assets which were impaired during the period	$ 10.1	$ 30.8	$ 31.9	$ 48.0
Impairment charge	3.6	14.8	15.6	28.3
Significant Unobservable Inputs (Level 3) [Member]
Fair Value, Assets and Liabilities Measured on Recurring and Nonrecurring Basis [Line Items]
Fair value of long-lived assets which were impaired during the period	$ 6.5	$ 16.0	$ 16.3	$ 19.7