Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	6 Months Ended
	Jun. 30, 2023	Jun. 30, 2022
OPERATING ACTIVITIES:
Net income	$ 91,930	$ 66,158
Adjustments to reconcile net cash provided (used) by operating activities:
Depreciation and amortization	56,053	57,149
Regulatory charges resulting from tax rate changes	0	11,693
Allowance for equity funds used during construction (equity AFUDC)	(1,134)	(1,138)
Changes in current assets and liabilities:
Trade and other accounts receivable	5,159	4,259
Affiliate receivables	207	17
Materials and supplies	6	(979)
Regulatory assets	(71)	(290)
Other current assets	1,175	1,225
Trade accounts payable	(1,126)	889
Affiliate payables	(3,013)	(5,069)
Regulatory liabilities	(125,505)	(1)
Other accrued liabilities	(370)	(2,955)
Other, including changes in long-term assets and liabilities:
Other, including changes in long-term assets and liabilities	(22,050)	2,282
Net cash provided (used) by operating activities	1,261	133,240
FINANCING ACTIVITIES:
Cash distributions to parent	(97,800)	(78,500)
Net cash provided (used) by financing activities	(97,800)	(78,500)
Property, plant and equipment:
Capital expenditures	(40,133)	(29,699)
Contributions and advances for construction costs	2,804	8,492
Disposal of property, plant and equipment, net	(2,368)	(1,760)
Advances to affiliate, net	136,236	(31,773)
Net cash provided (used) by investing activities	96,539	(54,740)
Increase (decrease) in cash	0	0
Cash at beginning of period	0	0
Cash at end of period	0	0
Additional Cash Flow Elements and Supplemental Cash Flow Information [Abstract]
Increases to property, plant and equipment, exclusive of equity AFUDC	(37,377)	(29,161)
Changes in related accounts payable and accrued liabilities	(2,756)	(538)
Capital expenditures	$ (40,133)	$ (29,699)