Investments (Details-3) - USD ($) $ in Thousands	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Equity method investment summarized assets [Abstract]
Total Current Assets	$ 227,265	$ 238,197
Total Assets	2,827,959	2,675,458
Equity method investment summarized liabilities and equity [Abstract]
Total Current Liabilities	125,563	157,156
Total Other Credits	708,561	659,407
Total Liabilities and Capitalization	2,827,959	2,675,458
ATC [Member]
Equity method investment summarized income statement [Abstract]
Operating revenues	911,314	818,921	$ 751,158
Operating expenses	(442,359)	(407,643)	(381,528)
Other income, net	1,407	2,452	1,171
Interest expense, net	(139,204)	(134,107)	(124,091)
Earnings before members' income taxes	331,158	279,623	$ 246,710
Equity method investment summarized assets [Abstract]
Total Current Assets	126,628	115,236
Total Noncurrent Assets	6,792,600	6,336,954
Total Assets	6,919,228	6,452,190
Equity method investment summarized liabilities and equity [Abstract]
Total Current Liabilities	482,440	495,919
Long-term debt	3,083,409	2,735,985
Total Other Credits	544,973	585,173
Total Equity	2,808,406	2,635,113
Total Liabilities and Capitalization	$ 6,919,228	$ 6,452,190