Pension and Other Postretirement Employee Benefit Plans - Pretax Pension and OPEB in AOCI (Details 1) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Pension Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Percent Above Which Amortization Of Net Gains And Losses Is Included In Annual Net Periodic Benefit Cost	10.00%
Defined Benefit Pension Plans, U.S. [Member]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax
Net gain/(loss)	$ (3,814)	$ (3,669)
Prior service credit/(cost)	237	278
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax	(3,577)	(3,391)
Defined Benefit Pension Plans, Non-U.S. [Member]
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax
Net gain/(loss)	(676)	(544)
Prior service credit/(cost)	18	12
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax	(658)	(532)
Defined Benefit Pension Plans and OPEB Plans [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan Percent Above Which Amortization Of Net Gains And Losses Is Included In Annual Net Periodic Benefit Cost	10.00%
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax
Net gain/(loss)	(133)	(176)
Prior service credit/(cost)	1	1
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), before Tax	$ (132)	$ (175)