Casualty, Environmental and Other Reserves - Narrative (Details)	3 Months Ended								12 Months Ended
	Dec. 31, 2017 USD ($) claim site $ / shares	Sep. 30, 2017 $ / shares	Jun. 30, 2017 $ / shares	Mar. 31, 2017 $ / shares	Dec. 30, 2016 USD ($) $ / shares	Sep. 23, 2016 $ / shares	Jun. 24, 2016 $ / shares	Mar. 25, 2016 $ / shares	Dec. 31, 2017 USD ($) claim site $ / shares	Dec. 30, 2016 USD ($) $ / shares	Dec. 25, 2015 USD ($) $ / shares	Dec. 26, 2014 USD ($)
Loss Contingencies [Line Items]
Reserves	$ 374,000,000				$ 374,000,000				$ 374,000,000	$ 374,000,000	$ 400,000,000	$ 418,000,000
Reduction in reserves										$ (28,000,000)
Earnings per share impact (in dollars per share) | $ / shares	$ 4.63	$ 0.51	$ 0.55	$ 0.39	$ 0.49	$ 0.48	$ 0.47	$ 0.37	$ 6.01	$ 1.81	$ 2.00
Casualty Reserves
Loss Contingencies [Line Items]
Reserves	$ 228,000,000				$ 229,000,000				$ 228,000,000	$ 229,000,000	$ 269,000,000	265,000,000
Self-insured retention amount per injury									$ 50,000,000
Individual claims expected to exceed self-insured retention amount | claim	0								0
Change in estimate recorded to adjust reserves											0
Reduction in reserves										(28,000,000)
Earnings from continuing operations										$ 18,000,000
Earnings per share impact (in dollars per share) | $ / shares										$ 0.02
Environmental
Loss Contingencies [Line Items]
Reserves	$ 90,000,000				95,000,000				$ 90,000,000	$ 95,000,000	82,000,000	94,000,000
Reduction in reserves										0
Environmental impaired site | site	214								214
Other Reserves
Loss Contingencies [Line Items]
Reserves	$ 56,000,000				$ 50,000,000				$ 56,000,000	50,000,000	$ 49,000,000	$ 59,000,000
Reduction in reserves										$ 0