Consolidated Condensed Statements of Income and Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Revenues
Electric	$ 593	$ 597	$ 1,563	$ 1,581
Gas	104	96	350	309
Total revenues	697	693	1,913	1,890
Expenses
Fuel	162	158	417	454
Purchased power	21	21	48	36
Operations and maintenance	153	127	472	386
Depreciation and amortization	97	89	279	262
Taxes, other than income	55	53	158	151
Total expenses	529	492	1,509	1,404
Income from operations	168	201	404	486
Other income
Allowance for equity funds used during construction	6	0	7	1
Other income, net	2	2	6	6
Total other income	8	2	13	7
Interest charges
Interest on long-term debt	26	27	80	83
Other interest	4	3	10	7
Allowance for borrowed funds used during construction	(3)	0	(4)	(1)
Total interest charges	27	30	86	89
Income before provision for income taxes	149	173	331	404
Provision for income taxes	31	67	65	156
Net income	118	106	266	248
Other comprehensive income, net of tax
Gain on cash flow hedges			1	1
Comprehensive income	118	106	267	249
Cost of Natural Gas Sold [Member]
Expenses
Cost of goods and services sold	$ 41	$ 44	$ 135	$ 115