Segment Reporting (Tables)

3 Months Ended

Mar. 31, 2026

Segment Reporting [Abstract]

Schedule of Segment Reporting Information, by Segment

Segment information:

	Three Months Ended March 31
	2026		2025
(Millions of Dollars)	Regulated electric utility		Regulated electric utility
Operating revenues	$	530	$	521
Electric fuel and purchased power	198		216
O&M expenses	86		88
Depreciation and amortization	119		112
Other segment expenses, net	17		24
Interest charges and financing costs	46		43
Income tax benefit	(20)		(21)
Net income	$	84	$	59