Investments (Details-3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Equity method investment summarized assets [Abstract]
Total Current Assets	$ 228,548	$ 227,265
Total Assets	3,155,420	2,827,959
Equity method investment summarized liabilities and equity [Abstract]
Total Current Liabilities	296,709	125,563
Total Other Credits	762,570	708,561
Total Liabilities and Capitalization	3,155,420	2,827,959
ATC [Member]
Equity method investment summarized income statement [Abstract]
Operating revenues	974,956	911,314	$ 818,921
Operating expenses	(472,610)	(442,359)	(407,643)
Other income, net	1,364	1,407	2,452
Interest expense, net	(167,152)	(139,204)	(134,107)
Earnings before members' income taxes	336,558	331,158	$ 279,623
Equity method investment summarized assets [Abstract]
Total Current Assets	137,522	126,628
Total Noncurrent Assets	7,590,778	6,792,600
Total Assets	7,728,300	6,919,228
Equity method investment summarized liabilities and equity [Abstract]
Total Current Liabilities	839,789	482,440
Long-term debt	3,156,253	3,083,409
Total Other Credits	638,916	544,973
Total Equity	3,093,342	2,808,406
Total Liabilities and Capitalization	$ 7,728,300	$ 6,919,228