Consolidated Condensed Statements of Income and Comprehensive Income (Unaudited) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018
Revenues
Electric	$ 520	$ 509	$ 931	$ 970
Gas	107	110	235	246
Total revenues	627	619	1,166	1,216
Expenses
Fuel	139	133	246	255
Purchased power	13	14	17	27
Cost of natural gas sold	$ 38	$ 39	$ 85	$ 94
Type of Cost, Good or Service [Extensible List]	us-gaap:OilAndGasMember	us-gaap:OilAndGasMember	us-gaap:OilAndGasMember	us-gaap:OilAndGasMember
Operations and maintenance	$ 132	$ 162	$ 262	$ 319
Depreciation and amortization	94	89	186	182
Taxes, other than income	52	51	102	103
Total expenses	468	488	898	980
Income from operations	159	131	268	236
Other income
Allowance for equity funds used during construction	2	1	4	1
Other income, net	3	2	5	4
Total other income	5	3	9	5
Interest charges
Interest expense	34	30	68	60
Allowance for borrowed funds used during construction	(1)	(1)	(2)	(1)
Total interest charges	33	29	66	59
Income before provision for income taxes	131	105	211	182
Provision for income taxes	24	20	40	34
Net income	107	85	171	148
Other comprehensive income, net of tax
Gain on cash flow hedges	0	1	0	1
Comprehensive income	$ 107	$ 86	$ 171	$ 149