Other Comprehensive Income / (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 25, 2015	Dec. 26, 2014	Dec. 27, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Comprehensive earnings	$ 1,969	$ 1,784	$ 2,277
Other Comprehensive Income (Loss):
Beginning Balance	(666)	(523)	(936)
(Loss) Income Before Reclassifications	(61)	(293)	534
Amounts Reclassified to Net Earnings	69	62	109
Tax (Expense) Benefit	(7)	88	(230)
Total Other Comprehensive (Loss) Income	1	(143)	413
Ending Balance	(665)	(666)	(523)
Pension and Other Post-Employment Benefits [Member]
Other Comprehensive Income (Loss):
Beginning Balance	(611)	(462)	(851)
(Loss) Income Before Reclassifications	(53)	(297)	510
Amounts Reclassified to Net Earnings	71	60	111
Tax (Expense) Benefit	(8)	88	(232)
Total Other Comprehensive (Loss) Income	10	(149)	389
Ending Balance	(601)	(611)	(462)
Other
Other Comprehensive Income (Loss):
Beginning Balance	(55)	(61)	(85)
(Loss) Income Before Reclassifications	(8)	4	24
Amounts Reclassified to Net Earnings	(2)	2	(2)
Tax (Expense) Benefit	1	0	2
Total Other Comprehensive (Loss) Income	(9)	6	24
Ending Balance	$ (64)	$ (55)	$ (61)