Pensions and Other Postretirement Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 29, 2014	Jun. 30, 2013	Jun. 29, 2014	Jun. 30, 2013
Retirement Plans
Components of net periodic benefit cost
Service cost	$ 200	$ 205	$ 397	$ 411
Interest cost	256	227	513	455
Expected return on plan assets	(407)	(361)	(809)	(724)
Amortization of prior service cost/(credit)	2	(1)	3	3
Recognized actuarial losses	118	172	231	340
Net periodic benefit cost	169	242	335	485
Other Benefit Plans
Components of net periodic benefit cost
Service cost	53	50	106	98
Interest cost	49	38	99	75
Expected return on plan assets	(1)	(2)	(3)	(3)
Amortization of prior service cost/(credit)	(8)	0	(17)	(1)
Recognized actuarial losses	34	27	68	55
Net periodic benefit cost	$ 127	$ 113	$ 253	$ 224