Consolidated Statements of Operations (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2022	Mar. 31, 2021
Income Statement [Abstract]
Operating revenues	$ 842	$ 888
Operating expenses:
Operation and maintenance	364	419
Depreciation and amortization	158	157
General taxes	74	83
Total operating expenses, net	596	659
Operating income	246	229
Other income (expense):
Interest expense	(100)	(98)
Interest income	13	0
Non-operating benefit costs, net	19	20
Other, net	15	4
Total other (expense) income	(53)	(74)
Income before income taxes	193	155
Provision for income taxes	35	22
Net income attributable to common shareholders	$ 158	$ 133
Basic earnings per share:
Net income attributable to common shareholders (dollars per share)	$ 0.87	$ 0.73
Diluted earnings per share:
Net income attributable to common shareholders (dollars per share)	$ 0.87	$ 0.73
Weighted-average common shares outstanding:
Basic (in shares)	182	181
Diluted (in shares)	182	182