Organization and Basis of Presentation (Consolidated Variable Interest Entities) (Details) (USD $) In Millions, unless otherwise specified	Jun. 30, 2014	Dec. 31, 2013	Jun. 30, 2013	Dec. 31, 2012
Assets [Abstract]
Cash and cash equivalents	$ 75	$ 52	$ 46	$ 65
Restricted cash	110	123
Accounts receivable	1,400	1,542
Property, plant and equipment, net	16,307	15,800
Securitized regulatory assets	135	231
Total Assets	26,189	25,935
Liabilities [Abstract]
Current portion long-term debt, including, capital leases	229	898
Current regulatory liabilities	150	302
Mortgage bonds, notes and other	7,329	6,618
Securitization bonds	0	105
Capital lease obligations	4	11
Variable Interest Entity, Primary Beneficiary Securitization [Member]
Assets [Abstract]
Cash and cash equivalents	0	0
Restricted cash	88	100
Accounts receivable	39	34
Inventories	0	0
Property, plant and equipment, net	0	0
Securitized regulatory assets	135	231
Other current and long-term assets	2	4
Total Assets	264	369
Liabilities [Abstract]
Accounts payable and accrued current liabilities	5	7
Current portion long-term debt, including, capital leases	201	196
Current regulatory liabilities	41	43
Mortgage bonds, notes and other	0	0
Securitization bonds	0	105
Capital lease obligations	0	0
Other current and long-term liabilities	8	8
Total Liabilities	255	359
Variable Interest Entity, Primary Beneficiary Other [Member]
Assets [Abstract]
Cash and cash equivalents	14	12
Restricted cash	6	8
Accounts receivable	12	16
Inventories	27	118
Property, plant and equipment, net	86	99
Securitized regulatory assets	0	0
Other current and long-term assets	7	9
Total Assets	152	262
Liabilities [Abstract]
Accounts payable and accrued current liabilities	8	23
Current portion long-term debt, including, capital leases	9	9
Current regulatory liabilities	0	0
Mortgage bonds, notes and other	18	21
Securitization bonds	0	0
Capital lease obligations	4	7
Other current and long-term liabilities	5	6
Total Liabilities	44	66
Variable Interest Entity, Primary Beneficiary [Member]
Assets [Abstract]
Cash and cash equivalents	14	12
Restricted cash	94	108
Accounts receivable	51	50
Inventories	27	118
Property, plant and equipment, net	86	99
Securitized regulatory assets	135	231
Other current and long-term assets	9	13
Total Assets	416	631
Liabilities [Abstract]
Accounts payable and accrued current liabilities	13	30
Current portion long-term debt, including, capital leases	210	205
Current regulatory liabilities	41	43
Mortgage bonds, notes and other	18	21
Securitization bonds	0	105
Capital lease obligations	4	7
Other current and long-term liabilities	13	14
Total Liabilities	$ 299	$ 425