Organization and Basis of Presentation (Consolidated Variable Interest Entities) (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Assets [Abstract]
Cash and cash equivalents	$ 52	$ 65	$ 68	$ 65
Restricted cash	123	122
Accounts receivable	1,542	1,336
Other current assets	209	215
Property, plant and equipment	15,800	14,684
Securitized regulatory assets	231	413
Other assets	198	197
Total Assets	25,935	26,339	26,009
Liabilities [Abstract]
Current portion long-term debt, including capital leases	898	817
Current regulatory liabilities	302	89
Other current liabilities	495	449
Mortgage bonds, notes and other	6,618	6,220
Securitization bonds	105	302
Capital lease obligations	11	12
Other long term liabilities	297	306
Variable Interest Entity Securitization [Member]
Assets [Abstract]
Cash and cash equivalents	0	0
Restricted cash	100	102
Accounts receivable	34	34
Inventories	0	0
Other current assets	0	0
Property, plant and equipment	0	0
Securitized regulatory assets	231	413
Other assets	4	7
Total Assets	369	556
Liabilities [Abstract]
Accounts payable and accrued current liabilities	7	11
Current portion long-term debt, including capital leases	196	177
Current regulatory liabilities	43	50
Other current liabilities	0	0
Mortgage bonds, notes and other	0	0
Securitization bonds	105	302
Capital lease obligations	0	0
Other long term liabilities	8	7
Total Liabilities	359	547
Variable Interest Entity, Primary Beneficiary [Member]
Assets [Abstract]
Cash and cash equivalents	12	10
Restricted cash	8	7
Accounts receivable	16	7
Inventories	118	141
Other current assets	1	1
Property, plant and equipment	99	93
Securitized regulatory assets	0	0
Other assets	8	11
Total Assets	262	270
Liabilities [Abstract]
Accounts payable and accrued current liabilities	23	14
Current portion long-term debt, including capital leases	9	8
Current regulatory liabilities	0	0
Other current liabilities	4	4
Mortgage bonds, notes and other	21	25
Securitization bonds	0	0
Capital lease obligations	7	11
Other long term liabilities	2	2
Total Liabilities	66	64
Consolidated Variable Interest Entity [Member]
Assets [Abstract]
Cash and cash equivalents	12	10
Restricted cash	108	109
Accounts receivable	50	41
Inventories	118	141
Other current assets	1	1
Property, plant and equipment	99	93
Securitized regulatory assets	231	413
Other assets	12	18
Total Assets	631	826
Liabilities [Abstract]
Accounts payable and accrued current liabilities	30	25
Current portion long-term debt, including capital leases	205	185
Current regulatory liabilities	43	50
Other current liabilities	4	4
Mortgage bonds, notes and other	21	25
Securitization bonds	105	302
Capital lease obligations	7	11
Other long term liabilities	10	9
Total Liabilities	$ 425	$ 611