Organization and Basis of Presentation (Details 1) (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010	Sep. 30, 2010	Dec. 31, 2009
Assets [Abstract]
Cash and cash equivalents	$ 46	$ 65	$ 84	$ 52
Restricted cash	73	120
Accounts receivable	1,206	1,393
Other current assets	249	197
Property, plant and equipment	13,422	12,992
Securitized regulatory assets	618	729
Other assets	192	206
Total Assets	24,780	24,896
Liabilities [Abstract]
Current portion long-term debt, including, capital leases	247	925
Other current liabilities	536	597
Mortgage bonds, notes and other	6,702	6,114
Securitization bonds	479	643
Capital lease obligations	27	43
Other long term liabilities	258	275
Variable Interest Entity Securitization [Member]
Assets [Abstract]
Cash and cash equivalents	0	0
Restricted cash	58	104
Accounts receivable	38	42
Inventories	0	0
Other current assets	0	0
Property, plant and equipment	0	0
Securitized regulatory assets	618	729
Other assets	10	13
Total Assets	724	888
Liabilities [Abstract]
Accounts payable and accrued current liabilities	4	17
Current portion long-term debt, including, capital leases	164	150
Other current liabilities	62	62
Mortgage bonds, notes and other	0	0
Securitization bonds	479	643
Capital lease obligations	0	0
Other long term liabilities	6	6
Total Liabilities	715	878
Variable Interest Entity, Primary Beneficiary [Member]
Assets [Abstract]
Cash and cash equivalents	8	4
Restricted cash	7	8
Accounts receivable	14	8
Inventories	145	99
Other current assets	1	1
Property, plant and equipment	58	54
Securitized regulatory assets	0	0
Other assets	6	9
Total Assets	239	183
Liabilities [Abstract]
Accounts payable and accrued current liabilities	38	27
Current portion long-term debt, including, capital leases	7	7
Other current liabilities	1	6
Mortgage bonds, notes and other	31	35
Securitization bonds	0	0
Capital lease obligations	20	23
Other long term liabilities	2	7
Total Liabilities	99	105
Consolidated Variable Interest Entity [Member]
Assets [Abstract]
Cash and cash equivalents	8	4
Restricted cash	65	112
Accounts receivable	52	50
Inventories	145	99
Other current assets	1	1
Property, plant and equipment	58	54
Securitized regulatory assets	618	729
Other assets	16	22
Total Assets	963	1,071
Liabilities [Abstract]
Accounts payable and accrued current liabilities	42	44
Current portion long-term debt, including, capital leases	171	157
Other current liabilities	63	68
Mortgage bonds, notes and other	31	35
Securitization bonds	479	643
Capital lease obligations	20	23
Other long term liabilities	8	13
Total Liabilities	814	983
Variable Interest Entity Restricted [Member]
Assets [Abstract]
Cash and cash equivalents	0	0
Restricted cash	64	112
Accounts receivable	40	44
Inventories	0	0
Other current assets	0	0
Property, plant and equipment	25	38
Securitized regulatory assets	618	729
Other assets	18	21
Total Assets	765	944
Liabilities [Abstract]
Accounts payable and accrued current liabilities	4	18
Current portion long-term debt, including, capital leases	171	157
Other current liabilities	64	66
Mortgage bonds, notes and other	31	35
Securitization bonds	479	643
Capital lease obligations	20	23
Other long term liabilities	7	12
Total Liabilities	$ 776	$ 954