Segment Reporting (Tables)

6 Months Ended

Jun. 30, 2025

Segment Reporting [Abstract]

Schedule of Segment Reporting Information, by Segment

Segment information:

	Three Months Ended June 30
	2025		2024
(Millions of Dollars)	Regulated electric utility		Regulated electric utility
Operating revenues	$	508	$	458
Electric fuel and purchased power	158		103
O&M expenses	83		83
Depreciation and amortization	115		136
Other segment expenses, net	22		26
Interest charges and financing costs	45		39
Income tax benefit	(16)		(18)
Net income	$	101	$	89

	Six Months Ended June 30
	2025		2024
(Millions of Dollars)	Regulated electric utility		Regulated electric utility
Operating revenues	$	1,029	$	886
Electric fuel and purchased power	374		263
O&M expenses	171		155
Depreciation and amortization	227		235
Other segment expenses, net	46		50
Interest charges and financing costs	88		74
Income tax benefit	(37)		(37)
Net income	$	160	$	146