| Document and Entity Information | Aug. 12, 2019 |
| Document And Entity Information [Line Items] | |
| Entity Registrant Name | CENTERPOINT ENERGY INC |
| Amendment Flag | false |
| Entity Central Index Key | 0001130310 |
| Document Type | 8-K |
| Document Period End Date | Aug. 12, 2019 |
| Entity Incorporation State Country Code | TX |
| Entity File Number | 1-31447 |
| Entity Tax Identification Number | 74-0694415 |
| Entity Address, Address Line One | 1111 Louisiana |
| Entity Address, City or Town | Houston |
| Entity Address, State or Province | TX |
| Entity Address, Postal Zip Code | 77002 |
| City Area Code | (713) |
| Local Phone Number | 207-1111 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Common Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Common Stock, $0.01 par value |
| Trading Symbol | CNP |
| Security Exchange Name | NYSE |
| [Member] | |
| Document And Entity Information [Line Items] | |
| Security Exchange Name | CHX |
| Series B Preferred Stock [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Depositary shares for 1/20 of 7.00% Series B Mandatory Convertible Preferred Stock, $0.01 par value |
| Trading Symbol | CNP/PB |
| Security Exchange Name | NYSE |
