Statement of Cash Flows (Unaudited) - USD ($) $ in Thousands	9 Months Ended
	Sep. 30, 2023	Sep. 30, 2022
OPERATING ACTIVITIES:
Net income	$ 937,523	$ 801,179
Adjustments to reconcile net cash provided (used) by operating activities:
Depreciation and amortization	388,474	389,421
Allowance for equity funds used during construction (equity AFUDC)	(45,182)	(14,815)
Regulatory credit resulting from tax rate changes	(23,064)	(9,040)
Changes in current assets and liabilities:
Affiliate receivables	2,110	270
Trade and other accounts receivable	38,977	15,421
Transportation and exchange gas receivables	(803)	312
Inventories	15,356	(64,454)
Regulatory assets	22,678	(21,961)
Other current assets	16,184	(9,285)
Affiliate payables	(10,288)	(8,555)
Trade accounts payable	(31,639)	14,040
Transportation and exchange gas payables	(1,902)	2,331
Accrued liabilities	23,670	(43,481)
Other, including changes in long-term assets and liabilities	(47,236)	34,779
Net cash provided (used) by operating activities	1,284,858	1,086,162
FINANCING ACTIVITIES:
Proceeds from other financing obligations	6,047	6,193
Payments on other financing obligations	(20,998)	(18,886)
Payments for debt issuance costs	0	(16)
Cash distributions to parent	(920,000)	(587,548)
Cash contributions from parent	0	128,000
Net cash provided (used) by financing activities	(934,951)	(472,257)
Property, plant and equipment:
Capital expenditures	(574,768)	(339,028)
Contributions and advances for construction costs, net	17,008	(1,545)
Disposal of property, plant and equipment, net	(33,334)	(21,876)
Advances to affiliate, net	249,115	(242,098)
Purchase of ARO Trust investments	(16,314)	(15,268)
Proceeds from sale of ARO Trust investments	8,386	5,910
Net cash provided (used) by investing activities	(349,907)	(613,905)
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	(719,631)	(346,056)
Changes in related accounts payable and accrued liabilities	144,863	7,028
Capital expenditures	$ (574,768)	$ (339,028)