Equity (Details) - USD ($) $ / shares in Units, $ in Millions	1 Months Ended		3 Months Ended
	Feb. 28, 2022	Jul. 31, 2021	Mar. 31, 2023	Mar. 31, 2022	Dec. 31, 2022	Jul. 20, 2021
Class of Stock [Line Items]
Preferred stock, outstanding (in shares)			800,000		800,000
Preferred stock			$ 790		$ 790
Preferred Stock Dividends and Other Adjustments [Abstract]
Preferred stock dividend requirement			12	$ 13
Total income allocated to preferred shareholders			12	13
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance			(31)	(64)
Prior service cost			(1)	0
Actuarial losses			0	1
Reclassification of deferred loss from cash flow hedges realized in net income			0	1
Net current period other comprehensive income (loss)			(1)	2
Ending Balance			(32)	(62)
Houston Electric
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance			0	0
Prior service cost			0	0
Actuarial losses			0	0
Reclassification of deferred loss from cash flow hedges realized in net income			0	0
Net current period other comprehensive income (loss)			0	0
Ending Balance			0	0
CERC
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance			16	10
Prior service cost			(1)	0
Actuarial losses			0	0
Reclassification of deferred loss from cash flow hedges realized in net income			0	0
Net current period other comprehensive income (loss)			(1)	0
Ending Balance			$ 15	$ 10
Chief Executive Officer
Preferred Stock Dividends and Other Adjustments [Abstract]
Retention incentive agreement, shares issued						1,000,000
Chief Executive Officer | Restricted Stock Units (RSUs)
Preferred Stock Dividends and Other Adjustments [Abstract]
Restricted stock units granted (in shares)	400,000	400,000
Remaining shares available to be awarded (in shares)		200,000
Common Stock
Class of Stock [Line Items]
Common stock, dividends declared per share (in dollars per share)			$ 0	$ 0
Common Stock dividends paid per share (in dollars per share)			0.190	0.170
Series A Preferred Stock
Class of Stock [Line Items]
Preferred stock, dividends declared (in dollars per share)			0	0
Preferred stock dividends paid per share (in dollars per share)			30.625	$ 30.625
Preferred stock, liquidation preference (in dollars per share)			$ 1,000
Preferred stock, outstanding (in shares)			800,000		800,000
Preferred stock			$ 790		$ 790
Preferred Stock Dividends and Other Adjustments [Abstract]
Preferred stock dividend requirement			$ 12	$ 13
Preferred Stock
Class of Stock [Line Items]
Preferred stock, outstanding (in shares)			800,000		800,000
Preferred stock			$ 790		$ 790