Pensions and Other Postemployment Benefits (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011	Jun. 30, 2012	Jun. 30, 2011
Pensions
Components of Net Periodic Benefit Costs (Credits)
Service cost	$ 40	$ 34	$ 80	$ 63
Interest cost	97	96	194	180
Expected return on plan assets	(121)	(115)	(242)	(217)
Amortization of prior service cost	3	4	6	8
Other adjustments (settlements, curtailments, etc)	0	0	0	7
Net periodic cost (credit)	19	19	38	41
OPEB
Components of Net Periodic Benefit Costs (Credits)
Service cost	3	3	6	6
Interest cost	12	12	24	23
Expected return on plan assets	(9)	(10)	(18)	(20)
Amortization of prior service cost	(51)	(51)	(102)	(99)
Other adjustments (settlements, curtailments, etc)	0	0	0	0
Net periodic cost (credit)	$ (45)	$ (46)	$ (90)	$ (90)