Pensions and Other Postretirement Benefits (Net Periodic Benefit Costs) (Details) (Pension Plans, Defined Benefit [Member], USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Mar. 31, 2011	Sep. 30, 2012	Sep. 30, 2011
Defined Contribution Pension [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	$ 16	$ 16		$ 48	$ 48
Interest cost	61	64		183	192
Expected return on plan assets	(74)	(77)		(224)	(234)
Amortization of actuarial losses	39	31		115	91
Curtailment (gains) losses			4		4
Net periodic pension/other postretirement benefit cost	42	34		122	101
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Service cost	5	5		16	14
Interest cost	14	15		43	47
Amortization of prior service cost	(3)	(3)		(9)	(9)
Amortization of actuarial losses	8	8		25	23
Net periodic pension/other postretirement benefit cost	$ 24	$ 25		$ 75	$ 75