Pension, OPEB and Savings Plans (Assumptions Used To Determine The Benefit Obligations And Net Periodic Benefit Costs) (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Defined Benefit Plan Disclosure [Line Items]
Expected Return on Plan Assets	8.00%
Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount Rate	4.20%	5.00%	5.51%
Rate of Compensation Increase	4.61%	4.61%	4.61%
Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount Rate	4.20%	5.00%	5.50%
Rate of Compensation Increase	4.61%	4.61%	4.61%
Administrative Expense	3.00%	5.00%	5.00%
Dental Costs	6.00%	6.00%	6.00%
Total of Service Cost and Interest Cost	$ 12	$ 11	$ 10
Postretirement Benefit Obligation	180	155	122
Total of Service Cost and Interest Cost	(9)	(9)	(8)
Postretirement Benefit Obligation	$ (149)	$ (128)	$ (102)
Other Benefits [Member] | Pre-65 Medical Costs [Member]
Defined Benefit Plan Disclosure [Line Items]
Immediate Rate	8.88%	8.00%	7.75%
Ultimate Rate	5.00%	5.00%	5.00%
Year Ultimate Rate Reached	2023	2016	2015
Other Benefits [Member] | Post-65 Medical Costs [Member]
Defined Benefit Plan Disclosure [Line Items]
Immediate Rate	7.98%	8.25%	8.75%
Ultimate Rate	5.00%	5.00%	5.00%
Year Ultimate Rate Reached	2019	2017	2016
Net Periodic Benefit Cost [Member] | Pension Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount Rate	5.00%	5.40%	5.91%
Expected Return on Plan Assets	8.00%	8.50%	8.50%
Rate of Compensation Increase	4.61%	4.61%	4.61%
Net Periodic Benefit Cost [Member] | Other Benefits [Member]
Defined Benefit Plan Disclosure [Line Items]
Discount Rate	5.00%	5.38%	5.90%
Expected Return on Plan Assets	8.00%	8.50%	8.50%
Rate of Compensation Increase	4.61%	4.61%	4.61%