Statement of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	6 Months Ended
	Jun. 30, 2012	Jun. 30, 2011
OPERATING ACTIVITIES:
Net income	$ 70,194	$ 75,062
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation	46,535	45,101
Regulatory credits	(404)	(534)
Amortization of deferred charges and credits	795	859
Allowance for equity funds used during construction	(719)	(407)
Changes in current assets and liabilities:
Trade accounts receivable	2,098	4,541
Affiliated receivables	2,250	84
Exchange gas due from others	2,296	7,780
Materials and supplies	439	499
Other current assets	(978)	(1,320)
Trade accounts payable	(2,465)	(2,620)
Affiliated payables	4,695	3,650
Exchange gas due to others	(2,295)	(7,781)
Other accrued liabilities	303	2,821
Changes in noncurrent assets and liabilities:
Deferred charges	(954)	(1,130)
Other deferred credits	2,639	2,748
Net cash provided by operating activities	124,429	129,353
FINANCING ACTIVITIES:
Capital contributions from parent	2,330	3,500
Distributions paid	(73,000)	(64,000)
Other	(1,719)	(1,424)
Net cash used in financing activities	(72,389)	(61,924)
Property, plant and equipment -
Capital expenditures	(47,147)	(36,245)
Proceeds from sales	4,748	1,150
Advances to affiliates	(9,438)	(32,332)
Net cash used in investing activities	(51,837)	(67,427)
NET INCREASE IN CASH	203	2
CASH AT BEGINNING OF PERIOD	37	5
CASH AT END OF PERIOD	$ 240	$ 7