CONSOLIDATED STATEMENTS OF INCOME - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Operating revenues
Electric, non-affiliates	$ 687	$ 668	$ 721
Regulated Operating Revenue, Electric, Affiliate	168	177	158
Natural gas	119	136	142
Other	0	0	1
Total operating revenues	974	981	1,022
Operating expenses
Electric fuel and purchased power, non-affiliates	13	11	13
Purchased power, affiliates	379	394	411
Cost of natural gas sold and transported	53	65	69
Operating and maintenance expenses	191	201	203
Conservation program expenses	13	12	12
Depreciation and amortization	156	138	126
Taxes (other than income taxes)	28	29	29
Total operating expenses	833	850	863
Operating income	141	131	159
Other Income and Expenses [Abstract]
Other expense, net	(8)	(1)	(3)
Allowance for funds used during construction — equity	5	3	9
Interest charges and financing costs
Interest charges — includes other financing costs of $1, $1 and $2, respectively	40	39	39
Allowance for funds used during construction — debt	(2)	(1)	(4)
Total interest charges and financing costs	38	38	35
Income before income taxes	100	95	130
Income tax (benefit) expense	(7)	16	32
Net income	$ 107	$ 79	$ 98