Other Comprehensive Income / (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 30, 2016	Dec. 25, 2015	Dec. 26, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Comprehensive earnings	$ 1,739	$ 1,969	$ 1,784
Other Comprehensive Income (Loss):
Beginning Balance	(665)	(666)	(523)
Loss Before Reclassifications	(13)	(61)	(293)
Amounts Reclassified to Net Earnings	51	69	62
Tax Benefit	(13)	(7)	88
Total Other Comprehensive Income	25	1	(143)
Ending Balance	(640)	(665)	(666)
Pension and Other Post-Employment Benefits
Other Comprehensive Income (Loss):
Beginning Balance	(601)	(611)	(462)
Loss Before Reclassifications	(16)	(53)	(297)
Amounts Reclassified to Net Earnings	50	71	60
Tax Benefit	(13)	(8)	88
Total Other Comprehensive Income	21	10	(149)
Ending Balance	(580)	(601)	(611)
Other
Other Comprehensive Income (Loss):
Beginning Balance	(64)	(55)	(61)
Loss Before Reclassifications	3	(8)	4
Amounts Reclassified to Net Earnings	1	(2)	2
Tax Benefit	0	1	0
Total Other Comprehensive Income	4	(9)	6
Ending Balance	$ (60)	$ (64)	$ (55)