Consolidated Statements of Comprehensive Income (Loss) (Unaudited) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2021	Jun. 30, 2020	Jun. 30, 2021	Jun. 30, 2020
Income Statement [Abstract]
Operating Revenue	[1]	$ 692	$ 624	$ 1,436	$ 1,296
Operating Expenses:
Fuel used in electric generation	[1]	120	95	252	199
Purchased power	[1]	27	25	43	38
Gas purchased for resale	[1]	50	34	131	91
Other operations and maintenance		117	93	216	183
Other operations and maintenance - affiliated suppliers		47	50	100	105
Impairment of assets and other charges		259	0	319	2
Depreciation and amortization		119	118	240	236
Other taxes	[1]	62	65	127	127
Total operating expenses		801	480	1,428	981
Operating income (loss)		(109)	144	8	315
Other income (expense), net		(12)	2	(6)	5
Interest charges, net of allowance for borrowed funds used during construction of $1, $1, $2 and $3	[2]	54	58	109	116
Income (loss) before income tax expense		(175)	88	(107)	204
Income tax expense (benefit)		(49)	21	(36)	44
Net Income (Loss) and Other Comprehensive Income (Loss)		(126)	67	(71)	160
Comprehensive Income (Loss) Attributable to Noncontrolling Interest		5	(2)	9	3
Comprehensive Income (Loss) Available to Common Shareholder		$ (131)	$ 69	$ (80)	$ 157

[1] See Note 12 for amounts attributable to affiliates.

[2] See Note 5 for amounts attributable to affiliates.