Summary of Significant Accounting Policies (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Significant Accounting Policies [Line Items]
Number of consolidated variable interest entities	4
Amount of removal costs recognized as a component of depreciation expense recorded as a regulatory liability	$ 349	$ 346
Amortization Period, Transition Property (in years)	12 to 14 years
AFUDC interest	10	6	4
AFUDC equity	8	6	5
Allowance for doubtful accounts	3	2
Provision for doubtful accounts	2	2	2
Restricted cash accounts	41	54
Amount of cash and cash equivalents that is held by transition and system restoration bond subsidiaries solely to support servicing the transition and system restoration bonds	207	266
Customer deposits included in other current liabilities	$ 21	$ 27