Retirement Benefits and Trusteed Assets (Details Textuals) (USD $)	12 Months Ended			1 Months Ended		12 Months Ended		1 Months Ended	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Jan. 31, 2012 Pension Plans, Defined Benefit [Member]	Jan. 31, 2011 Pension Plans, Defined Benefit [Member]	Dec. 31, 2012 Pension Plans, Defined Benefit [Member]	Dec. 31, 2011 Pension Plans, Defined Benefit [Member]	Jan. 31, 2012 Other Postretirement Benefit Plans, Defined Benefit [Member]	Dec. 31, 2012 Other Postretirement Benefit Plans, Defined Benefit [Member]	Dec. 31, 2011 Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]
Company contributions				$ 315,000,000	$ 229,000,000	$ 240,000,000	$ 209,000,000	$ 145,000,000	$ 140,000,000	$ 111,000,000
Allocation of Company Contributions in Lieu of Post-Employment Health Care Benefits	4,000
Time Period for Vesting of Allocation of Company Contributions in Lieu of Post-Employment Health Care Benefits	10 years
Company Retiree New Coverage Maximum	3,500
Company Retiree New Coverage Minimum	3,250
Company Retiree New Coverage after a Certain Date Maximum	4,000
Company Contribution to Employee Savings Plan	4.00%
Time period to pay benefit payments for qualified and unqualified plans						5 years			5 years
Time period for aggregate benefit payments for qualified and non qualtified benefit plans						5 years			5 years
Transfers between Level 2 and Level 3						0	0		0	0
Transfers between Level 1 and Level 2						0	0		0	0
Defined Contribution Plan, Cost Recognized	37,000,000	35,000,000	34,000,000
Health Care Trend Increase in Percentage Point	0.00%
Defined Benefit Plan, Effect of One Percentage Point Decrease on Accumulated Postretirement Benefit Obligation	264,000,000
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year									120,000,000
Defined Benefit Plan, Effect of One Percentage Point Increase on Service and Interest Cost Components	28,000,000
Defined Benefit Plan, Effect of One Percentage Point Increase on Accumulated Postretirement Benefit Obligation	279,000,000
Health Care Trend Decrease in Percentage Point	0.00%
Defined Benefit Plan, Effect of One Percentage Point Decrease on Service and Interest Cost Components	19,000,000
Prescription Drug Benefit, Effect of Subsidy on Net Periodic Postretirement Benefit Cost	6,000,000	6,000,000	7,000,000
Grantor Trust Balance	$ 14,000,000