Pension Plans, Postretirement and Other Employee Benefits (Details Textual) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011 Age	Dec. 31, 2010	Dec. 31, 2009
Pension Plans, Postretirement and Other Employee Benefits (Textual) [Abstract]
Expected contributions in 2012	$ 48
Employer contributions	45
Pension Fund assets available to fund pension benefit obligations	529
Pension Plans, Postretirement and Other Employee Benefits (Additional Textual) [Abstract]
Pension benefit obligations	784
Pension benefit obligations with funding requirements	710
Pension benefit obligations with no funding requirements	74
Significant concentrations of risk defined as individual assets that exceed 5% of total plan assets	More than 5%
Targeted pension plan allocations in equity securities	70.00%
Targeted pension plan allocations in debt securities	30.00%
Acceptable tolerance limit of investment allocations for securities	5.00%
Minimum retirement age for eligible employees of the post retirement plans	55
Minimum years of service for eligible employees of the post retirement plans	10 years
Minimum age for eligible employees of post retirement plan	45
Weighted average assumed health care cost trend rate used in determining the 2011 accumulated postretirement benefit obligation	8.0% declining to 4.5% over suceeding periods	7.5% declining to 5.0% over suceeding periods	8.3% declining to 5.0% over suceeding periods
Maximum percentage of salary deferral allowed under the Employee Stock Ownership Plans	75.00%
Employee matching contribution	50% of employee's contibutions up to 8% of employee's salary
Expense recorded relating to employee matching contribution	18	17	10
Employee matching contribution beginning in 2012	100% of contributions on first 3% and 50% on next 2%
Pension Plans, Defined Benefit [Member]
Pension Plans, Postretirement and Other Employee Benefits (Textual) [Abstract]
Expected contributions in 2012	9
United States Postretirement Benefit Plans of US Entity, Defined Benefit [Member]
Pension Plans, Postretirement and Other Employee Benefits (Textual) [Abstract]
Defined benefit plan effect of one percentage point increase on service and interest cost components	Less than $1 million
One percentage point increase effect on postretirement benefit obligation	10
Defined benefit plan effect of one percentage point decrease on service and interest cost components	Less than $1 million
One percentage point decrease effect on postretirement benefit obligation	8
Employer contributions	9	9
Pension Fund assets available to fund pension benefit obligations	$ 0	$ 0	$ 0