Statement of Cash Flows (Unaudited) (USD $) In Thousands, unless otherwise specified	3 Months Ended
	Mar. 31, 2012	Mar. 31, 2011
OPERATING ACTIVITIES:
Net income	$ 38,308	$ 39,683
Adjustments to reconcile net income to net cash provided by (used in) operating activities:
Depreciation	23,310	22,558
Regulatory credits	(289)	(267)
Amortization of deferred charges and credits	404	425
Allowance for equity funds used during construction	(213)	(120)
Changes in current assets and liabilities:
Trade accounts receivable	(719)	2,120
Affiliated receivables	2,241	16
Exchange gas due from others	1,832	4,675
Materials and supplies	277	336
Other current assets	487	397
Trade accounts payable	(2,565)	(3,656)
Affiliated payables	744	(1,086)
Exchange gas due to others	(1,833)	(4,676)
Other accrued liabilities	14,347	15,302
Changes in noncurrent assets and liabilities:
Deferred charges	(340)	(1,179)
Other deferred credits	1,218	1,399
Net cash provided by operating activities	77,209	75,927
FINANCING ACTIVITIES:
Capital contributions from parent	1,230	3,500
Distributions paid	(28,000)	(26,000)
Other	(2,428)	(2,302)
Net cash used in financing activities	(29,198)	(24,802)
Property, plant and equipment -
Capital expenditures	(21,000)	(13,820)
Proceeds from sales	5,127	876
Advances to affiliates	(32,170)	(38,117)
Net cash used in investing activities	(48,043)	(51,061)
NET INCREASE (DECREASE) IN CASH	(32)	64
CASH AT BEGINNING OF PERIOD	37	5
CASH AT END OF PERIOD	$ 5	$ 69