CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Operating revenues
Electric, non-affiliates	$ 800	$ 733	$ 687
Electric, affiliates	202	189	168
Natural gas	198	182	119
Other	1	1	0
Total operating revenues	1,201	1,105	974
Operating expenses
Electric fuel and purchased power, non-affiliates	17	20	13
Purchased power, affiliates	446	408	379
Cost of natural gas sold and transported	116	117	53
Operating and maintenance expenses	223	198	191
Conservation program expenses	13	13	13
Depreciation and amortization	158	147	156
Taxes (other than income taxes)	31	28	28
Total operating expenses	1,004	931	833
Operating income	197	174	141
Other Income and Expenses [Abstract]
Other expense, net	(2)	(1)	(8)
Allowance for funds used during construction — equity	7	5	5
Interest charges and financing costs
Interest charges — includes other financing costs of $1, $1 and $1, respectively	45	42	40
Allowance for funds used during construction — debt	(3)	(2)	(2)
Total interest charges and financing costs	42	40	38
Income before income taxes	160	138	100
Income tax expense (benefit)	35	30	(7)
Net income	$ 125	$ 108	$ 107