Employee Benefit Plans - Schedule of Pre-tax Change in Other Comprehensive Loss (Income) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 30, 2016	Dec. 25, 2015
Pension Plans
Components of Other Comprehensive Loss (Income) [Abstract]
(Gains) Losses	$ (131)	$ 38
Expense (Income) recognized in the income statement
Amortization of net losses	41	48	$ 70
Settlement gain	11	(1)	(2)
Curtailment loss	4	0
Amortization of prior service costs	0	0	0
Estimated amount to be expensed in the future period	43
Post-retirement Benefits
Components of Other Comprehensive Loss (Income) [Abstract]
(Gains) Losses	(17)	(22)
Expense (Income) recognized in the income statement
Amortization of net losses	0	3	4
Settlement gain	0	0	0
Curtailment loss	0	0
Amortization of prior service costs	$ 0	$ 0	$ (1)