Consolidated Statements of Income and Comprehensive Income - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Revenues
Electric	$ 2,052	$ 1,964	$ 2,018
Gas	418	432	401
Total revenues	2,470	2,396	2,419
Expenses
Fuel	588	561	639
Purchased power	46	104	79
Cost of natural gas sold	153	159	135
Operations & maintenance	513	538	529
Depreciation and amortization	350	328	313
Taxes, other than income	198	193	192
Total expenses	1,848	1,883	1,887
Income from operations	622	513	532
Other income
Allowance for other funds used during construction	2	24	17
Other income, net	8	7	3
Total other income	10	31	20
Interest charges
Interest expense	120	117	118
Allowance for borrowed funds used during construction	(1)	(11)	(8)
Total interest charges	119	106	110
Income before provision for income taxes	513	438	442
Provision for income taxes	197	152	166
Net income	316	286	276
Other comprehensive income, net of tax
Gain on cash flow hedges	1	1	4
Total other comprehensive income, net of tax	1	1	4
Comprehensive income	$ 317	$ 287	$ 280