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v3.24.0.1

Short-term Borrowings and Long-term Debt - Narrative (Details) $ / shares in Units, $ in Millions |  |  |  | 1 Months Ended | 12 Months Ended
--- | --- | --- | --- | --- | ---
Dec. 15, 2023 | Aug. 01, 2023 $ / shares | Jan. 17, 2023 USD ($) | Jul. 31, 2023 USD ($) numberOfSeries | Apr. 30, 2023 USD ($) numberOfSeries | Dec. 31, 2023 USD ($) shares
Debt Instrument [Line Items] |  |  |  |  |  |
Debt instrument, convertible, conversion ratio |  | 27.1278 |  |  |  |
Conversion price percentage |  | 25.00% |  |  |  |
Long-term Debt |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Principal amount of debt issued |  |  |  |  |  | $ 3,023
Maximum |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Debt instrument, convertible, conversion ratio |  |  |  |  |  | 33.9097
Debt instrument, convertible, number of equity instruments (in shares) | shares |  |  |  |  |  | 33,909,700
Convertible Debt |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Debt instrument, convertible, conversion price (in dollar per shares) | $ / shares |  | $ 36.86 |  |  |  |
Debt instrument, redemption price (as a percent) |  | 100.00% |  |  |  |
CERC Floating Rate Senior Notes Zero Point Six Five Percentage Due 2024 | Senior Notes | Long-term Debt |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Principal amount of debt issued |  |  |  |  |  | $ 350
Debt instrument, redemption price (as a percent) | 100.00% |  |  |  |  |
SIGECO |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Remarketing Agreement to Remarket, Number of Series | numberOfSeries |  |  |  | 2 | 5 |
Proceeds from Issuance of Secured Tax Exempt Debt |  |  |  | $ 38 | $ 148 |
Percentage of property additions |  |  |  |  |  | 70.00%
Long-term debt, gross |  |  |  |  |  | $ 847
Additional debt issuable |  |  |  |  |  | 966
SIGECO | Environmental Improvement Revenue Bonds, Series 2013 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Principal amount of debt issued |  |  |  |  | 107 |
SIGECO | Environmental Improvement Revenue Bonds, Series 2014 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Principal amount of debt issued |  |  |  |  | $ 41 |
SIGECO | Environmental Improvement Revenue Bonds, Series 2015 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Debt instrument interest rate (as a percent) |  |  |  | 4.25% |  |
SIGECO | CNP First Mortgage Bonds 4.00% Due 2044 | First Mortgage Bonds | Long-term Debt |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Principal amount of debt issued |  |  | $ 11 |  |  | $ 11
Debt instrument interest rate (as a percent) |  |  |  |  |  | 4.00%
Debt instrument, redemption price (as a percent) |  |  | 100.00% |  |  |
SIGECO | Mount Vernon | Environmental Improvement Revenue Bonds, Series 2015 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Principal amount of debt issued |  |  |  | $ 23 |  |
SIGECO | Warrick County | Environmental Improvement Revenue Bonds, Series 2015 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Principal amount of debt issued |  |  |  | $ 15 |  |
Houston Electric |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Additional first mortgage bonds and general mortgage bonds that could be issued |  |  |  |  |  | $ 4,800
Houston Electric | General mortgage bonds, 2.35% to 6.95%, due 2026 to 2053 |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Secured Debt |  |  |  |  |  | $ 7,600
Houston Electric | General mortgage bonds, 2.35% to 6.95%, due 2026 to 2053 | Maximum |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Debt instrument interest rate (as a percent) |  |  |  |  |  | 6.95%
Houston Electric | Bonds Pollution Control Due |  |  |  |  |  |
Debt Instrument [Line Items] |  |  |  |  |  |
Secured Debt |  |  |  |  |  | $ 68
Percentage of property additions |  |  |  |  |  | 70.00%

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