Pension and Other Postretirement Benefits (Details 1) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Pensions
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	$ 130	$ 99	$ 91
Interest cost	374	314	317
Expected return on plan assets	(446)	(361)	(343)
Amortization of prior service cost	14	13	13
Other adjustments (settlements, curtailments, etc.)	6	0	0
Pensions & OPEB mark-to-market adjustment	(729)	(264)	(483)
Net periodic cost (credit)	807	329	561
OPEB
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Service cost	13	10	12
Interest cost	48	45	64
Expected return on plan assets	(40)	(36)	(36)
Amortization of prior service cost	(203)	(193)	(175)
Other adjustments (settlements, curtailments, etc.)	0	0	0
Pensions & OPEB mark-to-market adjustment	(36)	(22)	(16)
Net periodic cost (credit)	$ (146)	$ (152)	$ (119)