Employee Benefit Plans (Narrative) (Details) (USD $) In Millions, unless otherwise specified	1 Months Ended	12 Months Ended
	Jan. 31, 2011	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Previous Elgible Age For Post Retirement Benefits With 10 Years of Service			55
New Elgible Age For Postretirement Benefits With 10 Years Of Service			58
Other postretirement benefit plan obligation reduction	$ 71
Aggregate actual returns on pension and other postretirement plan assets			273	624
Expected return on pension and other postretirement plan assets			519	479
Federal subsidy received			5
Accumulated benefit obligation			95	80
Expected contribution to voluntary employees beneficiary association		16
Employer contributions			38	39	42
Decrease in Other Postretirement Benefit Obligations Due to Federal Subsidy			170
Expected Annual Decrease in Other Postretirement Benefit Obligations Due to Federal Subsidy			20
Dominion [Member]
Federal subsidy received				5
Accumulated benefit obligation			4,500	4,100
Medicare Part D subsidies [Member]
2012			$ 5
Real Estate [Member]
Defined benefit plan, actual plan asset allocations			3.00%
US Equity [Member]
Defined benefit plan, actual plan asset allocations			28.00%
Non US Equity [Member]
Defined benefit plan, actual plan asset allocations			18.00%
Fixed Income Investments [Member]
Defined benefit plan, actual plan asset allocations			33.00%
Other than Securities Investment [Member]
Defined benefit plan, actual plan asset allocations			18.00%