Condensed Consolidated Statement of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities:
Net income	$ 320,011	$ 271,342
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation and amortization	204,449	197,112
Allowance for equity funds used during construction (equity AFUDC)	(10,748)	(10,959)
Changes in operating assets and liabilities:
Receivables - affiliates	(278)	1,352
Receivables - trade and other	28,402	1,448
Transportation and exchange gas receivable	3,853	(2,026)
Inventories	(25,186)	295
Payables - affiliates	(547)	(4,589)
Payables - trade	19,858	(25,480)
Accrued liabilities	(8,483)	23,645
Reserve for rate refunds	(98,217)	68,407
Asset retirement obligation removal costs	(10,307)	(24,619)
Other, net	9,511	66,741
Net cash provided by operating activities	432,318	562,669
Cash flows from financing activities:
Cash distributions to parent	(318,000)	(186,000)
Cash contributions from parent	164,000	203,000
Other, net	8,108	9,143
Net cash provided by (used in) financing activities	(145,892)	26,143
Cash flows from investing activities:
Property, plant and equipment additions, net of equity AFUDC	(432,167)	(444,542)
Contributions and advances for construction costs	39,185	25,977
Disposal of property, plant and equipment, net	(2,939)	(1,786)
Advances to affiliate, net	114,155	(158,788)
Return of capital from unconsolidated affiliates	1,381	916
Purchase of ARO Trust investments	(37,521)	(44,975)
Proceeds from sale of ARO Trust investments	29,589	32,968
Other, net	1,887	1,340
Net cash used in investing activities	(286,430)	(588,890)
Decrease in cash	(4)	(78)
Cash at beginning of period	113	185
Cash at end of period	109	107
Increase to property, plant and equipment	(474,716)	(457,104)
Changes in related accounts payable and accrued liabilities	42,549	12,562
Property, plant and equipment additions, net of equity AFUDC	$ (432,167)	$ (444,542)