Equity (CenterPoint Energy) (Details)					1 Months Ended			12 Months Ended
	May 06, 2020 USD ($) $ / shares shares	Apr. 01, 2020 $ / shares	Oct. 01, 2018 USD ($) $ / shares shares	Aug. 22, 2018 USD ($) $ / shares shares	Feb. 28, 2023 shares	Feb. 28, 2022 shares	Jul. 31, 2021 shares	Dec. 31, 2022 USD ($) day $ / shares shares	Dec. 31, 2021 USD ($) $ / shares shares	Dec. 31, 2020 USD ($) $ / shares shares	Sep. 01, 2021 shares	Jul. 20, 2021 shares	May 07, 2021 $ / shares
Cumulative preferred stock, outstanding (in shares) | shares								800,000	800,000	2,402,400
Preferred stock, value outstanding								$ 790,000,000	$ 790,000,000	$ 2,363,000,000
Income allocated to preferred shareholders								49,000,000	95,000,000	144,000,000
Amortization of beneficial conversion feature								0	0	32,000,000
Income allocated to preferred shareholders								49,000,000	95,000,000	176,000,000
Cumulative preferred stock, aggregate liquidation preference								800	800
Proceeds from issuance of Common Stock, net								0	0	672,000,000
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance								(64,000,000)	(90,000,000)
Other comprehensive income (loss) from unconsolidated affiliates								0	3,000,000
Prior service cost								(1,000,000)	1,000,000
Actuarial losses								8,000,000	7,000,000
Settlement								67,000,000	4,000,000
Reclassification of deferred loss from cash flow hedges realized in net income								1,000,000	2,000,000
Tax benefit (expense)								(2,000,000)	(7,000,000)
Net current period other comprehensive income (loss)								33,000,000	26,000,000	8,000,000
Ending Balance								(31,000,000)	(64,000,000)	(90,000,000)
Chief Executive Officer
Shares authorized for issuance under long-term incentive plans (in shares) | shares												1,000,000
Chief Executive Officer | Restricted Stock Units (RSUs)
RSUs granted (in shares) | shares						400,000	400,000
Chief Executive Officer | Restricted Stock Units (RSUs) | Subsequent Event | Forecast
RSUs granted (in shares) | shares					200,000
Houston Electric
Amortization of beneficial conversion feature								0	0	0
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance								0	0
Other comprehensive income (loss) from unconsolidated affiliates								0	0
Prior service cost								0	0
Actuarial losses								0	0
Settlement								0	0
Reclassification of deferred loss from cash flow hedges realized in net income								0	0
Tax benefit (expense)								0	0
Net current period other comprehensive income (loss)								0	0	15,000,000
Ending Balance								0	0	0
CERC Corp
Amortization of beneficial conversion feature								0	0	0
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Beginning Balance								10,000,000	10,000,000
Other comprehensive income (loss) from unconsolidated affiliates								0	0
Prior service cost								(1,000,000)	1,000,000
Actuarial losses								1,000,000	0
Settlement								0	0
Reclassification of deferred loss from cash flow hedges realized in net income								0	0
Tax benefit (expense)								(4,000,000)	(1,000,000)
Net current period other comprehensive income (loss)								6,000,000	0	0
Ending Balance								16,000,000	10,000,000	$ 10,000,000
Pension and Other Postretirement Plans
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Remeasurement of pension and other postretirement plans								(40,000,000)	16,000,000
Pension and Other Postretirement Plans | Houston Electric
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Remeasurement of pension and other postretirement plans								0	0
Pension and Other Postretirement Plans | CERC Corp
Accumulated Other Comprehensive Income (Loss) [Roll Forward]
Remeasurement of pension and other postretirement plans								$ 10,000,000	$ 0
Common Stock
Stub cash dividend (in dollars per share) | $ / shares								$ 0.7200	$ 0.6600	$ 0.9000
Common stock, dividends paid per share (in dollars per share) | $ / shares								$ 0.7000	$ 0.6500	0.7400
Stock issued (in shares) | shares	41,977,612
Common stock issued upon conversion (in shares) | shares									35,921,441
Common stock issued per share price | $ / shares	$ 16.08
Proceeds from issuance of Common Stock, net	$ 673,000,000
Shares authorized for issuance under long-term incentive plans (in shares) | shares								30,000,000
Common Stock | Previous Dividend or Distribution
Stub cash dividend (in dollars per share) | $ / shares		$ 0.2900
Common Stock | Revised Dividend or Distribution
Stub cash dividend (in dollars per share) | $ / shares		$ 0.1500
Series A Preferred Stock
Preferred stock dividends declared per share | $ / shares								$ 61.2500	$ 61.2500	91.8750
Preferred stock, dividends paid per share (in dollars per share) | $ / shares								61.2500	$ 61.2500	$ 61.2500
Preferred stock liquidation preference (per share) | $ / shares				$ 1,000				$ 1,000
Cumulative preferred stock, outstanding (in shares) | shares								800,000	800,000	800,000
Preferred stock, value outstanding								$ 790,000,000	$ 790,000,000	$ 790,000,000
Income allocated to preferred shareholders								$ 49,000,000	$ 49,000,000	$ 49,000,000
Stock issued (in shares) | shares				800,000
Proceeds from the issuance of convertible stock				$ 790,000,000
Cumulative preferred stock, aggregate liquidation preference				$ 800,000,000
Preferred stock dividend rate								6.125%
Preferred stock redemption price (per share) | $ / shares								$ 1,000
Preferred stock convertible threshold (in days) | day								120
Series A Preferred Stock | London Interbank Offered Rate (LIBOR)
Preferred stock, basis spread (as a percent)								3.27%
Series A Preferred Stock | 120 Days After Conclusion of Review or Appeal
Preferred stock redemption price (per share) | $ / shares								$ 1,020
Preferred stock redemption percentage liquidation value								102.00%
Series B Preferred Stock
Preferred stock dividends declared per share | $ / shares								$ 0	$ 35.0000	$ 87.5000
Preferred stock, dividends paid per share (in dollars per share) | $ / shares								0	$ 52.5000	$ 70.0000
Preferred stock liquidation preference (per share) | $ / shares			$ 1,000					$ 1,000
Cumulative preferred stock, outstanding (in shares) | shares								0	0	977,400
Preferred stock, value outstanding								$ 0	$ 0	$ 950,000,000
Income allocated to preferred shareholders								0	46,000,000	68,000,000
Income allocated to preferred shareholders								$ 49,000,000	$ 95,000,000	$ 144,000,000
Stock issued (in shares) | shares			2,550,000
Ownership (percentage)			5.00%
Cumulative preferred stock, aggregate liquidation preference			$ 978,000,000
Preferred stock dividend rate								7.00%
Conversion rate per share (in shares) | shares											36.7677
Preferred stock converted to common stock (in shares) | shares									977,400
Series C Preferred Stock
Preferred stock dividends declared per share | $ / shares								$ 0	$ 0	$ 0.6100
Preferred stock, dividends paid per share (in dollars per share) | $ / shares								0	$ 0.1600	$ 0.4500
Preferred stock liquidation preference (per share) | $ / shares	$ 1,000							$ 1,000					$ 1,000
Cumulative preferred stock, outstanding (in shares) | shares								0	0	625,000
Preferred stock, value outstanding								$ 0	$ 0	$ 623,000,000
Income allocated to preferred shareholders								$ 0	$ 0	$ 27,000,000
Stock issued (in shares) | shares	725,000
Proceeds from the issuance of convertible stock	$ 724,000,000
Preferred stock converted to common stock (in shares) | shares									625,000
Common stock issued upon conversion (in shares) | shares									40,822,990
Conversion price (in dollars per share) | $ / shares													$ 15.31
Depositary Shares
Stock issued (in shares) | shares			19,550,000
Proceeds from the issuance of convertible stock			$ 950,000,000
Depositary share par value (in dollars per share) | $ / shares			$ 50