Pensions and Other Postretirement Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 29, 2013	Sep. 30, 2012	Sep. 29, 2013	Sep. 30, 2012
Retirement Plans [Member]
Components of net periodic benefit cost
Service cost	$ 204	$ 163	$ 615	$ 492
Interest cost	226	218	681	659
Expected return on plan assets	(360)	(307)	(1,084)	(927)
Amortization of prior service cost (credit)	1	2	4	4
Amortization of net transition obligation	0	1	0	1
Recognized actuarial losses	169	123	509	371
Curtailments and Settlements			0	(1)
Net periodic benefit cost	240	200	725	599
Other Benefit Plans [Member]
Components of net periodic benefit cost
Service cost	49	42	147	131
Interest cost	37	41	112	123
Expected return on plan assets	(1)	(1)	(4)	(3)
Amortization of prior service cost (credit)	(1)	(1)	(2)	(3)
Amortization of net transition obligation	0	0	0	0
Recognized actuarial losses	29	21	84	59
Curtailments and Settlements			0	0
Net periodic benefit cost	$ 113	$ 102	$ 337	$ 307