CONDENSED CONSOLIDATED INCOME STATEMENTS - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Income Statement [Abstract]
Operating revenues	$ 2,009.5	$ 1,772.0	$ 5,159.0	$ 4,452.2
Operating expenses
Cost of sales	570.5	469.7	1,736.2	1,396.8
Other operation and maintenance	596.2	533.4	1,204.2	1,064.2
Depreciation and amortization	368.9	336.6	728.8	670.0
Property and revenue taxes	69.0	67.5	147.4	143.0
Total operating expenses	1,604.6	1,407.2	3,816.6	3,274.0
Operating income	404.9	364.8	1,342.4	1,178.2
Equity in earnings of transmission affiliates	51.9	46.8	105.5	91.6
Other income, net	26.5	40.6	44.6	84.7
Interest expense	220.8	200.6	443.8	392.6
Other expense	(142.4)	(113.2)	(293.7)	(216.3)
Income before income taxes	262.5	251.6	1,048.7	961.9
Income tax expense	19.5	41.6	80.2	129.3
Net income	243.0	210.0	968.5	832.6
Preferred stock dividends of subsidiary	0.3	0.3	0.6	0.6
Net loss attributed to noncontrolling interests	2.7	1.6	1.7	1.6
Net income attributed to common shareholders	$ 245.4	$ 211.3	$ 969.6	$ 833.6
EPS
Basic (in dollars per share)	$ 0.77	$ 0.67	$ 3.04	$ 2.64
Diluted (in dollars per share)	$ 0.76	$ 0.67	$ 3.02	$ 2.64
Weighted average common shares outstanding
Basic (in shares)	320.3	315.9	319.3	315.8
Diluted (in shares)	322.2	316.2	320.7	316.1