CONDENSED STATEMENTS OF CONSOLIDATED CASH FLOWS (Unaudited) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Cash Flows from Operating Activities:
Net Income	$ 316	$ 300	$ 230
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	262	248	229
Deferred income taxes	144	208	247
Amortization of deferred financing costs	13	9	9
Write-down of natural gas inventory	11	6	6
Equity in earnings of unconsolidated affiliates, net of distributions	8	13	(3)
Changes in other assets and liabilities:
Accounts receivable and unbilled revenues, net.	67	120	238
Accounts receivable/payable, affiliates	(14)	6	3
Inventory	20	(52)	231
Taxes receivable	62	(16)	(47)
Accounts payable	(101)	(35)	(160)
Fuel cost over (under) recovery	(70)	(9)	(5)
Interest and taxes accrued	6	5	(34)
Non-trading derivatives, net	(10)	(5)	29
Margin deposits, net.	34	7	116
Other current assets	11	(20)	46
Other current liabilities	(12)	(14)	57
Other assets	(3)	(7)	1
Other liabilities	22	(21)	(14)
Other, net	3	(21)	0
Net cash provided by operating activities	769	722	1,179
Cash Flows from Investing Activities:
Capital expenditures	(644)	(917)	(690)
(Increase) decrease in notes receivable from unconsolidated affiliates	0	0	323
Investment in unconsolidated affiliates	(12)	(18)	(115)
Other, net	10	20	(3)
Net cash used in investing activities	(646)	(915)	(485)
Cash Flows from Financing Activities:
Increase (decrease) in short-term borrowings, net	9	(2)	(98)
Revolving credit facility, net	0	0	(926)
Proceeds from commercial paper, net	102	183	0
Payments of long-term debt	(606)	(45)	(7)
Cash paid for debt exchange	(58)	0	0
Proceeds from long-term debt	550	0	0
Increase (decrease) in notes payable to affiliates	(106)	57	432
Dividends to parent	0	0	(100)
Debt issuance costs	(14)	0	0
Other, net	0	0	5
Net cash provided by (used in) financing activities	(123)	193	(694)
Net Decrease in Cash and Cash Equivalents	0	0	0
Cash and Cash Equivalents at Beginning of the Year	1	1	1
Cash and Cash Equivalents at End of the Year	1	1	1
Cash Payments:
Interest, net of capitalized interest	177	191	203
Income taxes (refunds), net	(20)	141	(31)
Non-cash transactions:
Accounts payable related to capital expenditures	$ 53	$ 98	$ 53