Pensions and Other Postretirement Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Oct. 02, 2011	Sep. 30, 2012	Oct. 02, 2011
Retirement Plans [Member]
Components of net periodic benefit cost
Service cost	$ 163	$ 146	$ 492	$ 433
Interest cost	218	214	659	641
Expected return on plan assets	(307)	(279)	(927)	(834)
Amortization of prior service cost/ (credit)	2	3	4	7
Amortization of net transition obligation	1	0	1	1
Recognized actuarial losses	123	97	371	291
Curtailments and Settlements	0	0	(1)	0
Net periodic benefit cost	200	181	599	539
Other Benefit Plans [Member]
Components of net periodic benefit cost
Service cost	42	38	131	112
Interest cost	41	47	123	141
Expected return on plan assets	(1)	0	(3)	(1)
Amortization of prior service cost/ (credit)	(1)	(1)	(3)	(2)
Amortization of net transition obligation	0	0	0	0
Recognized actuarial losses	21	11	59	34
Curtailments and Settlements	0	0	0	0
Net periodic benefit cost	$ 102	$ 95	$ 307	$ 284