Pension Savings And Other Postretirement Benefit Plans (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		1 Months Ended			3 Months Ended						3 Months Ended
	Mar. 31, 2013	Mar. 31, 2012	Mar. 31, 2013 Frozen United States Pension Plans of US Entity, Defined Benefit [Member]	Feb. 28, 2013 Frozen United States Pension Plans of US Entity, Defined Benefit [Member]	Dec. 31, 2012 Frozen United States Pension Plans of US Entity, Defined Benefit [Member]	Mar. 31, 2013 Foreign Pension Plans, Defined Benefit	Mar. 31, 2012 Foreign Pension Plans, Defined Benefit	Mar. 31, 2013 U.S.	Mar. 31, 2012 U.S.	Aug. 31, 2012 Canadian Other Postretirement Benefit Plans, Change in Benefit Obligation [Member] Other Postretirement Benefit Plans, Defined Benefit [Member]	Aug. 31, 2012 U.S. Other Postretirement Benefit Plans, Change in Benefit Obligation [Member] Other Postretirement Benefit Plans, Defined Benefit [Member]	Mar. 31, 2013 Required Contributions [Member]	Mar. 31, 2013 Required Contributions [Member] Frozen United States Pension Plans of US Entity, Defined Benefit [Member]	Mar. 31, 2013 Discretionary Contributions [Member] Frozen United States Pension Plans of US Entity, Defined Benefit [Member]
Defined Benefit Plan, Net Periodic Benefit Cost [Abstract]
Service cost- benefits earned during the period						$ 10	$ 8	$ 11	$ 10
Interest cost on projected benefit obligation						33	35	61	66
Expected return on plan assets						(28)	(30)	(84)	(75)
Amortization of prior service cost						0	0	4	6
Amortization of net losses						16	12	53	46
Total defined benefit pension cost						31	25	45	53
Pension Savings and Other Postretirement Benefit Plans (Textuals) [Abstract]
Contributions to pension plans						30		868					34	834
Pension and Other Postretirement Benefit Plans, Accumulated Other Comprehensive Income (Loss), Net Gains (Losses), before Tax				93
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate				3.82%	3.61%
Defined Benefit Plan, Assumptions Used Calculating Net Periodic Benefit Cost, Expected Long-term Return on Assets			4.75%
Defined Benefit Plan, Fair Value of Plan Assets				2,072
Expected Current Year Contributions To Funded Pension Plans, Minimum												275
Expected Current Year Contributions To Funded Pension Plans, Maximum												325
Expense recognized for contributions to defined savings plans	26	27
Postretirement benefit cost (credit)	(2)	3
Defined Benefit Plan, Benefit Obligation										$ 18	$ 56