Short-Term Borrowings And Long-Term Debt (Short-Term Borrowings) (Details) (USD $) In Millions, unless otherwise specified	Sep. 30, 2013	Dec. 31, 2012
Short-term Debt [Line Items]
Short-term borrowings	$ 2,226	$ 2,136
Texas Competitive Electric Holdings Company LLC [Member]
Short-term Debt [Line Items]
Program funding under the accounts receivable securitization program	172	82
Texas Competitive Electric Holdings Company LLC [Member] | Revolving Credit Facility [Member]
Short-term Debt [Line Items]
Short-term borrowings	$ 2,054	$ 2,054
Short-term borrowings, weighted average interest rate (as a percent)	4.68%	4.40%