Pension Benefits - Schedule of Assumptions Used (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2016	Dec. 27, 2015	Dec. 28, 2014	Dec. 29, 2013
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Calculation term, market-related value		3 years
Increase to pension obligation due to change in mortality table assumptions		$ 117.0
Qualified Plans [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate		4.60%	4.05%
Estimated increase in compensation level used to calculate benefit obligation		2.96%	2.89%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate used to calculate net periodic benefit cost		4.05%	4.90%	4.00%
Estimated increase in compensation level use to calculate net periodic benefit cost		2.89%	2.87%	3.50%
Expected long-term rate of return on assets		7.01%	7.02%	7.85%
Non-Qualified Plans [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Benefit Obligation [Abstract]
Discount rate		4.40%	3.90%
Estimated increase in compensation level used to calculate benefit obligation		2.50%	2.50%
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Discount rate used to calculate net periodic benefit cost		3.90%	4.60%	3.70%
Estimated increase in compensation level use to calculate net periodic benefit cost		2.50%	2.50%	3.00%
Scenario, Forecast [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Service and interest costs	$ 18.1
Scenario, Forecast [Member] | Minimum [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Spot rate used in calculation of service and interest costs	0.84%
Scenario, Forecast [Member] | Maximum [Member]
Defined Benefit Plan, Weighted Average Assumptions Used in Calculating Net Periodic Benefit Cost [Abstract]
Spot rate used in calculation of service and interest costs	5.18%