Segment Reporting (Tables)

9 Months Ended

Sep. 30, 2025

Segment Reporting [Abstract]

Schedule of Segment Reporting Information, by Segment

Segment information:

	Three Months Ended Sept. 30
	2025		2024
(Millions of Dollars)	Regulated electric utility		Regulated electric utility
Operating revenues	$	655	$	594
Electric fuel and purchased power	208		163
O&M expenses	86		82
Depreciation and amortization	118		109
Other segment expenses, net	18		19
Interest charges and financing costs	45		40
Income tax expense	20		5
Net income	$	160	$	176

	Nine Months Ended Sept. 30
	2025		2024
(Millions of Dollars)	Regulated electric utility		Regulated electric utility
Operating revenues	$	1,684	$	1,480
Electric fuel and purchased power	582		426
O&M expenses	257		237
Depreciation and amortization	345		344
Other segment expenses, net	64		69
Interest charges and financing costs	133		114
Income tax benefit	(17)		(32)
Net income	$	320	$	322