CONDENSED STATEMENTS OF CONSOLIDATED COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Net income (Loss)	$ 121	$ 270	$ (973)	$ 634
Other comprehensive income (loss):
Adjustment to pension and other postretirement plans, net of tax	1	2	3	5
Net deferred gain (loss) from cash flow hedges, net of tax	0	(2)	0	(3)
Reclassification of deferred loss from cash flow hedges realized in net income	0	0	0	1
Reclassification of net deferred losses from cash flow hedges	0	0	15	0
Other comprehensive income (loss) from unconsolidated affiliates	1	(2)	(2)	(2)
Total	2	(2)	16	1
Comprehensive Income Net of Tax Before Preferred Stock Dividend	123	268	(957)	635
Income allocated to preferred shareholders	52	29	127	88
Comprehensive income (loss)	71	239	(1,084)	547
Other Comprehensive (Income) Loss, Defined Benefit Plan, after Reclassification Adjustment, Tax, Attributable to Parent	1	0	3	2
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax	0	0	0	0
Other Comprehensive Income (Loss), Reclassification Adjustment from AOCI on Derivatives, Tax	0	0	0	0
Tax benefit (expense) on Other Comprehensive lncome (loss) from unconsolidated affiliates	0	0	0	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax	0	0	4	0
Houston Electric [Member]
Net income (Loss)	157	185	277	312
Other comprehensive income (loss):
Net deferred gain (loss) from cash flow hedges, net of tax	0	0	0	(1)
Reclassification of net deferred losses from cash flow hedges	0	0	15	0
Total	0	0	15	(1)
Comprehensive income (loss)	157	185	292	311
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax	0	0	0	0
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), after Reclassification, Tax	0	0	4	0
CERC Corp [Member]
Net income (Loss)	(4)	(7)	76	159
Other comprehensive income (loss):
Total	0	0	0	0
Comprehensive income (loss)	$ (4)	$ (7)	$ 76	$ 159