Condensed Consolidated Statements of Income (unaudited) - USD ($) shares in Thousands, $ in Thousands	3 Months Ended		9 Months Ended
	Sep. 30, 2025	Sep. 30, 2024	Sep. 30, 2025	Sep. 30, 2024
Revenues
Revenues	$ 790,610	$ 833,239	$ 2,281,072	$ 2,420,670
Expenses
Total expenses	738,564	982,959	2,112,859	4,181,092
Operating income (loss)
Operating income (loss)	52,046	(149,720)	168,213	(1,760,422)
Retirement defined benefits credit—other than service costs	817	849	2,653	2,851
Interest expense, net	(26,211)	(32,085)	(87,679)	(96,076)
Allowance for borrowed funds used during construction	1,500	1,331	4,379	4,061
Allowance for equity funds used during construction	3,821	3,300	11,108	10,276
Interest income	6,960	3,662	27,162	9,929
Gain (loss) on sale of subsidiaries and impairment loss on assets sold and held for sale	1,013	0	(12,376)	0
Income (loss) before income taxes	39,946	(172,663)	113,460	(1,829,381)
Income tax expense (benefit)	8,728	(49,954)	28,540	(479,109)
Income (loss) from continuing operations	31,218	(122,709)	84,920	(1,350,272)
Preferred stock dividends of subsidiaries	471	471	1,417	1,417
Income (loss) from continuing operations for common stock	30,747	(123,180)	83,503	(1,351,689)
Income (loss) from discontinued operations	0	18,778	0	(6,075)
Net income (loss) for common stock	$ 30,747	$ (104,402)	$ 83,503	$ (1,357,764)
Continuing operations - Basic earnings (loss) per common share (in dollars per share)	$ 0.18	$ (1.08)	$ 0.48	$ (12.11)
Discontinued operations - Basic earnings (loss) per common share (in dollars per share)	0	0.16	0	(0.05)
Basic earnings (loss) per common share (in dollars per share)	0.18	(0.91)	0.48	(12.16)
Continuing operations - Diluted earnings (loss) per common share (in dollars per share)	0.18	(1.08)	0.48	(12.11)
Discontinued operations - Diluted earnings (loss) per common share (in dollars per share)	0	0.16	0	(0.05)
Diluted earnings (loss) per common share (in dollars per share)	$ 0.18	$ (0.91)	$ 0.48	$ (12.16)
Weighted-average number of common shares outstanding:
Basic (in shares)	172,617	114,358	172,531	111,636
Diluted (in shares)	172,916	114,358	172,939	111,636
Electric utility
Revenues
Revenues	$ 787,428	$ 829,617	$ 2,268,276	$ 2,410,526
Expenses
Total expenses	724,635	934,181	2,065,002	4,096,175
Operating income (loss)
Operating income (loss)	62,793	(104,564)	203,274	(1,685,649)
Other
Revenues
Revenues	3,182	3,622	12,796	10,144
Expenses
Total expenses	13,929	48,778	47,857	84,917
Operating income (loss)
Operating income (loss)	$ (10,747)	$ (45,156)	$ (35,061)	$ (74,773)