Condensed Consolidated Statement of Cash Flows (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012
Cash flows from operating activities:
Net income	$ 271,342	$ 183,426
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	197,112	199,451
Allowance for equity funds used during construction (equity AFUDC)	(10,959)	(9,935)
Changes in operating assets and liabilities:
Receivables - affiliates	1,352	3,370
Receivables - trade and other	1,448	13,093
Transportation and exchange gas receivable	(2,026)	1,022
Inventories	295	1,199
Payables - affiliates	(4,589)	13,078
Payables - trade	(25,480)	(14,067)
Accrued liabilities	23,645	(1,930)
Reserve for rate refunds	68,407	0
Asset retirement obligation removal costs	(24,619)	(30,646)
Other, net	66,741	25,722
Net cash provided by operating activities	562,669	383,783
Cash flows from financing activities:
Additions to long-term debt	0	398,804
Retirement of long-term debt	0	(325,000)
Debt issue costs	0	(4,304)
Cash distributions to parent	(186,000)	(196,259)
Cash contributions from parent	203,000	117,000
Other, net	9,143	(4,507)
Net cash provided by (used in) financing activities	26,143	(14,266)
Cash flows from investing activities:
Property, plant and equipment additions, net of equity AFUDC	(418,565)	(326,998)
Disposal of property, plant and equipment, net	(1,786)	9,920
Advances to affiliate, net	(158,788)	(64,186)
Return of capital from unconsolidated affiliates	916	11,327
Contributions to unconsolidated affiliates	0	(5,806)
Purchase of ARO Trust investments	(44,975)	(27,134)
Proceeds from sale of ARO Trust investments	32,968	32,471
Other, net	1,340	825
Net cash used in investing activities	(588,890)	(369,581)
Increase (decrease) in cash	(78)	(64)
Cash at beginning of period	185	164
Cash at end of period	107	100
Increase to property, plant and equipment	(446,092)	(327,634)
Changes in related accounts payable and accrued liabilities	27,527	636
Property, plant and equipment additions, net of equity AFUDC	$ (418,565)	$ (326,998)