Pensions and Other Postretirement Benefits (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jul. 03, 2016	Jun. 28, 2015	Jul. 03, 2016	Jun. 28, 2015
Retirement Plans
Components of net periodic benefit cost
Service cost	$ 226	$ 249	$ 452	$ 497
Interest cost	233	248	466	497
Expected return on plan assets	(493)	(455)	(985)	(910)
Amortization of prior service cost/(credit)	(1)	1	0	1
Recognized actuarial losses	124	187	248	374
Curtailments and settlements	4	0	5	4
Net periodic benefit cost	93	230	186	463
Other Benefit Plans
Components of net periodic benefit cost
Service cost	55	65	110	129
Interest cost	39	46	79	93
Expected return on plan assets	(1)	(1)	(3)	(3)
Amortization of prior service cost/(credit)	(8)	(9)	(16)	(17)
Recognized actuarial losses	34	50	68	100
Curtailments and settlements	0	0	0	0
Net periodic benefit cost	$ 119	$ 151	$ 238	$ 302