Employee Benefit Plans (Pre-Tax Change in Other Comprehensive Loss (Income) and Accumulated Other Comprehensive Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Pension Benefits [Member]
Components of other comprehensive loss (income) [Abstract]
Losses (Gains)	$ 60	$ 305
Expense (Income) recognized in income statement [Abstract]
Amortization of net losses	70	57	$ 100
Settlement gain	(2)	(1)	(2)
Amortization of prior service costs	0	0	0
Estimated amount to be expensed in the future period	48
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Losses	900
Prior Service Costs (Credits)	0
Total	900
Post-retirement Benefits [Member]
Components of other comprehensive loss (income) [Abstract]
Losses (Gains)	(7)	(8)
Expense (Income) recognized in income statement [Abstract]
Amortization of net losses	4	5	14
Settlement gain	0	0	0
Amortization of prior service costs	(1)	$ (1)	$ (1)
Estimated amount to be expensed in the future period	2
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax [Abstract]
Losses	49
Prior Service Costs (Credits)	0
Total	$ 49