Retirement Benefits and Trusteed Assets Retirement Benefits and Trusteed Assets (Details Textuals) (USD $)	3 Months Ended
	Mar. 31, 2013	Dec. 31, 2012
Defined Benefit Plan Disclosure [Line Items]
Contribution of Common Stock to Pension Plan	$ 50,000,000
Retiree Health Care Allowance	3,250
Remeasurement Reduction to Post Retirement Benefit Obligation	258,000,000	439,000,000
Remeasurement Reduction to Post Retirement Benefit Obligation Liability	721,000,000	1,200,000,000
Remeasurement Decrease in Benefit Cost for Postretirement Plans	69,000,000
Annual Decrease in Other Postretirement Benefits Costs due to Remeasurement	40,000,000
Pension Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Pension Contributions	100,000,000
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year	215,000,000
Other Postretirement Benefit Plans, Defined Benefit [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Estimated Future Employer Contributions in Current Fiscal Year	120,000,000
Defined Benefit Plan, Contributions by Employer	$ 145,000,000
Defined Benefit Plan, Assumptions Used Calculating Benefit Obligation, Discount Rate	4.30%	4.15%