Condensed Consolidated Statements of Income and Comprehensive Income (Unaudited) - USD ($) shares in Thousands, $ in Millions	3 Months Ended
	Mar. 31, 2017	Mar. 31, 2016
Revenues, net	$ 530	$ 487
Operating expenses:
Purchased power and fuel	141	149
Generation, transmission and distribution	81	66
Administrative and other	68	61
Depreciation and amortization	84	82
Taxes other than income taxes	33	30
Total operating expenses	407	388
Income from operations	123	99
Interest expense, net	30	27
Other income:
Allowance for equity funds used during construction	2	7
Miscellaneous income (expense), net	1	(1)
Other income, net	3	6
Income before income tax expense	96	78
Income tax expense	23	17
Net income and Comprehensive income	73	61
Other Comprehensive Income (Loss), Pension and Other Postretirement Benefit Plans, Net Unamortized Gain (Loss) Arising During Period, Net of Tax	(1)	0
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest	$ 72	$ 61
Weighted-average shares outstanding (in thousands):
Weighted Average Number of Shares Outstanding, Basic and Diluted	89,003	88,833
Earnings per share:
Earnings Per Share, Basic and Diluted	$ 0.82	$ 0.68
Dividends declared per common share	$ 0.32	$ 0.30