Reportable Segments - Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2026	Mar. 31, 2025
Segment Reporting Information [Line Items]
Expenditures for Long-lived Assets	$ 1,174	$ 1,340
CenterPoint Energy
Segment Reporting Information [Line Items]
Number of reportable segments	true
Houston Electric
Segment Reporting Information [Line Items]
Number of reportable segments	true
Expenditures for Long-lived Assets	$ 768	579
CERC
Segment Reporting Information [Line Items]
Number of reportable segments	true
Expenditures for Long-lived Assets	$ 319	$ 291