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Stock-Based Incentive Compensation Plans and Employee Benefit Plans - Plan Assets (Details)
$ in Millions
 12 Months Ended
Dec. 31, 2023
USD ($)
shares
Dec. 31, 2022
USD ($)
Dec. 31, 2021
USD ($)
Jan. 01, 2022
plan
Jan. 01, 2020
plan
Savings Plan [Abstract]          
Defined contribution plan cost $ 67 $ 72 $ 58    
Postemployment Benefits [Abstract]          
Postemployment Benefits, Period Expense (1) 4 3    
Benefit expense related to deferred compensation plans $ (1) 1 3    
Savings Plan          
Savings Plan [Abstract]          
Number of defined benefit plans to be merged | plan       1 1
Number of Common stock held by the savings plan (in shares) | shares 6,589,241        
Percentage of investment in common stocks (in hundredths) 7.00%        
Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value $ 1,204 1,212 2,072    
Obligation to return cash received as collateral from securities lending (94) (47)      
Financial instruments (4) 0      
Defined benefits plan, fair value of plan assets, excluding investments measured at net asset value $ 744 $ 708      
Discount rate (as a percent) 4.95% 5.15%      
Contributions in 2023 $ 32 $ 35      
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]          
2024 141        
2025 143        
2026 137        
2027 135        
2028 133        
2029-2033 606        
Pension Plan | Qualified Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Contributions in 2023 24        
Expected Minimum Contributions in 2024 2        
Pension Plan | Nonqualified Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Contributions in 2023 8        
Expected Minimum Contributions in 2024 7        
Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value $ 112 $ 109 132    
Discount rate (as a percent) 4.95% 5.15%      
Contributions in 2023 $ 7 $ 8      
Expected Minimum Contributions in 2024 8        
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]          
2024 14        
2025 16        
2026 17        
2027 19        
2028 20        
2029-2033 107        
Level 1 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 229 199      
Obligation to return cash received as collateral from securities lending (94) (47)      
Financial instruments 0 0      
Level 2 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 515 509      
Obligation to return cash received as collateral from securities lending 0 0      
Financial instruments (4) 0      
Level 3 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
Obligation to return cash received as collateral from securities lending 0 0      
Financial instruments 0 0      
U.S. equity | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 30 29      
U.S. equity | Level 1 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 30 29      
U.S. equity | Level 2 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
U.S. equity | Level 3 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
Cash | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 21 7      
Cash | Level 1 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 21 7      
Cash | Level 2 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
Cash | Level 3 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
Investment grade or above | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 469 467      
Investment grade or above | Level 1 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
Investment grade or above | Level 2 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 469 467      
Investment grade or above | Level 3 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
Cash received as collateral from securities lending | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 94 47      
Cash received as collateral from securities lending | Level 1 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 94 47      
Cash received as collateral from securities lending | Level 2 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
Cash received as collateral from securities lending | Level 3 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
U.S. treasuries and government agencies | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 178 163      
U.S. treasuries and government agencies | Level 1 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 178 163      
U.S. treasuries and government agencies | Level 2 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
U.S. treasuries and government agencies | Level 3 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
Mortgage backed securities | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 15 6      
Mortgage backed securities | Level 1 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
Mortgage backed securities | Level 2 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 15 6      
Mortgage backed securities | Level 3 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
Asset backed securities | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 1 2      
Asset backed securities | Level 1 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
Asset backed securities | Level 2 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 1 2      
Asset backed securities | Level 3 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
Municipal bonds | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 25 24      
Municipal bonds | Level 1 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
Municipal bonds | Level 2 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 25 24      
Municipal bonds | Level 3 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
Mutual funds | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value $ 113 $ 109      
Mutual funds | International equities | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, actual allocation (as a percent) 8.00% 8.00%      
Mutual funds | U.S. equity | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, actual allocation (as a percent) 20.00% 18.00%      
Mutual funds | Fixed income | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, actual allocation (as a percent) 72.00% 74.00%      
Mutual funds | Level 1 | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value $ 113 $ 109      
Mutual funds | Level 2 | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
Mutual funds | Level 3 | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
International government bonds | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 9 10      
International government bonds | Level 1 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
International government bonds | Level 2 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 9 10      
International government bonds | Level 3 | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
Common Collective Trust Funds | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value $ 460 $ 504      
Common Collective Trust Funds | International equities | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, actual allocation (as a percent) 40.00% 40.00%      
Common Collective Trust Funds | U.S. equity | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, actual allocation (as a percent) 59.00% 56.00%      
Common Collective Trust Funds | Fixed income | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, actual allocation (as a percent) 1.00% 4.00%      
Benefit Obligation          
Postemployment Benefits [Abstract]          
Postemployment benefit obligations $ 5 $ 9      
Other non-qualified plans benefit obligations deferred compensation 26 28      
Benefit obligations related to split-dollar life insurance arrangements $ 46 22      
Minimum | U.S. equity | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 17.00%        
Minimum | U.S. equity | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 14.00%        
Minimum | International equity | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 9.00%        
Minimum | International equity | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 3.00%        
Minimum | Real estate | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 2.00%        
Minimum | Fixed income | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 54.00%        
Minimum | Fixed income | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 69.00%        
Minimum | Cash | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 0.00%        
Minimum | Cash | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 0.00%        
Maximum | U.S. equity | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 27.00%        
Maximum | U.S. equity | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 24.00%        
Maximum | International equity | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 19.00%        
Maximum | International equity | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 13.00%        
Maximum | Real estate | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 11.00%        
Maximum | Fixed income | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 64.00%        
Maximum | Fixed income | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 79.00%        
Maximum | Cash | Pension Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 2.00%        
Maximum | Cash | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 2.00%        
Common Stock | CenterPoint Energy | Savings Plan          
Savings Plan [Abstract]          
Maximum limit of account balance in company stock (as a percent) 25.00%        
Houston Electric          
Savings Plan [Abstract]          
Defined contribution plan cost $ 23 23 20    
Postemployment Benefits [Abstract]          
Postemployment Benefits, Period Expense 0 1 1    
Benefit expense related to deferred compensation plans 0 0 0    
Houston Electric | Pension Plan | Qualified Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Contributions in 2023 0        
Expected Minimum Contributions in 2024 0        
Houston Electric | Pension Plan | Nonqualified Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Contributions in 2023 0        
Expected Minimum Contributions in 2024 0        
Houston Electric | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value $ 86 $ 84 104    
Discount rate (as a percent) 4.95% 5.15%      
Contributions in 2023 $ 0 $ 1      
Expected Minimum Contributions in 2024 1        
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]          
2024 6        
2025 6        
2026 7        
2027 8        
2028 9        
2029-2033 49        
Houston Electric | Mutual funds | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value $ 86 $ 84      
Houston Electric | Mutual funds | International equities | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, actual allocation (as a percent) 9.00% 8.00%      
Houston Electric | Mutual funds | U.S. equity | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, actual allocation (as a percent) 19.00% 17.00%      
Houston Electric | Mutual funds | Fixed income | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, actual allocation (as a percent) 72.00% 74.00%      
Houston Electric | Mutual funds | Level 1 | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value $ 86 $ 84      
Houston Electric | Mutual funds | Level 2 | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
Houston Electric | Mutual funds | Level 3 | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
Houston Electric | Benefit Obligation          
Postemployment Benefits [Abstract]          
Postemployment benefit obligations 2 3      
Other non-qualified plans benefit obligations deferred compensation 3 4      
Benefit obligations related to split-dollar life insurance arrangements $ 1 1      
Houston Electric | Minimum | U.S. equity | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 13.00%        
Houston Electric | Minimum | International equity | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 3.00%        
Houston Electric | Minimum | Fixed income | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 69.00%        
Houston Electric | Minimum | Cash | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 0.00%        
Houston Electric | Maximum | U.S. equity | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 23.00%        
Houston Electric | Maximum | International equity | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 13.00%        
Houston Electric | Maximum | Fixed income | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 79.00%        
Houston Electric | Maximum | Cash | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 2.00%        
CERC Corp          
Savings Plan [Abstract]          
Defined contribution plan cost $ 20 22 23    
Postemployment Benefits [Abstract]          
Postemployment Benefits, Period Expense 0 1 2    
Benefit expense related to deferred compensation plans 0 0 0    
CERC Corp | Pension Plan | Qualified Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Contributions in 2023 0        
Expected Minimum Contributions in 2024 0        
CERC Corp | Pension Plan | Nonqualified Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Contributions in 2023 0        
Expected Minimum Contributions in 2024 0        
CERC Corp | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value $ 26 $ 25 $ 29    
Discount rate (as a percent) 4.95% 5.15%      
Contributions in 2023 $ 4 $ 4      
Expected Minimum Contributions in 2024 4        
Defined Benefit Plan, Estimated Future Benefit Payments [Abstract]          
2024 5        
2025 6        
2026 6        
2027 7        
2028 7        
2029-2033 36        
CERC Corp | Mutual funds | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value $ 26 $ 25      
CERC Corp | Mutual funds | International equities | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, actual allocation (as a percent) 6.00% 6.00%      
CERC Corp | Mutual funds | U.S. equity | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, actual allocation (as a percent) 22.00% 20.00%      
CERC Corp | Mutual funds | Fixed income | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, actual allocation (as a percent) 71.00% 74.00%      
CERC Corp | Mutual funds | Level 1 | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value $ 26 $ 25      
CERC Corp | Mutual funds | Level 2 | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
CERC Corp | Mutual funds | Level 3 | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Plan assets, fair value 0 0      
CERC Corp | Benefit Obligation          
Postemployment Benefits [Abstract]          
Postemployment benefit obligations 3 4      
Other non-qualified plans benefit obligations deferred compensation 1 1      
Benefit obligations related to split-dollar life insurance arrangements $ 0 $ 0      
CERC Corp | Minimum | U.S. equity | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 15.00%        
CERC Corp | Minimum | International equity | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 2.00%        
CERC Corp | Minimum | Fixed income | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 68.00%        
CERC Corp | Minimum | Cash | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 0.00%        
CERC Corp | Maximum | U.S. equity | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 25.00%        
CERC Corp | Maximum | International equity | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 12.00%        
CERC Corp | Maximum | Fixed income | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 78.00%        
CERC Corp | Maximum | Cash | Other Postretirement Benefits Plan          
Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items]          
Target allocation (as a percent) 2.00%