Condensed Consolidated Statement of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011
Cash flows from operating activities:
Net Income	$ 183,426	$ 206,224
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	199,451	196,834
Allowance for equity funds used during construction (Equity AFUDC)	(9,935)	(8,643)
Changes in operating assets and liabilities:
Receivables - affiliates	3,370	(529)
Receivables - others	13,093	3,677
Inventories	1,199	29,531
Payables - affiliates	13,078	9,763
Payables - others	(14,067)	13,816
Accrued liabilities	(1,930)	27,413
Asset retirement obligation removal costs	(30,646)	(34,508)
Other, net	26,744	(4,399)
Net cash provided by operating activities	383,783	439,179
Cash flows from financing activities:
Additions to long-term debt	398,804	372,518
Retirement of long-term debt	(325,000)	(300,000)
Debt issue costs	(4,304)	(3,811)
Cash distributions to parent	(196,259)	(152,000)
Cash contributions from parent	117,000	100,000
Other, net	(4,507)	(7,671)
Net cash provided by (used in) financing activities	(14,266)	9,036
Cash flows from investing activities:
Property, plant and equipment additions, net of equity AFUDC*	(326,998)	(267,522)
Disposal of property, plant and equipment, net	9,920	(639)
Advances to affiliates, net	(64,186)	(172,910)
Return of capital from unconsolidated affiliates	11,327	1,925
Contributions to unconsolidated affiliates	(5,806)	(13,120)
Purchase of ARO Trust investments	(27,134)	(36,577)
Proceeds from sale of ARO Trust investments	32,471	47,901
Other, net	825	(7,301)
Net cash used in investing activities	(369,581)	(448,243)
Increase (decrease) in cash	(64)	(28)
Cash at beginning of period	164	148
Cash at end of period	$ 100	$ 120