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v3.24.1.u1

Short-term Borrowings and Long-term Debt - Narrative (Details) $ / shares in Units, $ in Millions |  | 1 Months Ended | 3 Months Ended |
--- | --- | --- | --- | ---
Aug. 01, 2023 $ / shares | Feb. 29, 2024 USD ($) | Mar. 31, 2024 USD ($) shares | Dec. 31, 2023 USD ($)
Debt Instrument [Line Items] |  |  |  |
Debt instrument, convertible, conversion ratio | 27.1278 |  |  |
Conversion price percentage | 25.00% |  |  |
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% |  |  |
First Mortgage Bonds 3.50% Due 2024 | SIGECO |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Debt instrument, interest rate, stated percentage |  |  | 3.50% |
Debt instrument, redemption price, principal amount redeemed |  |  | $ 22 |
Debt instrument, redemption price, percentage of principal amount redeemed |  |  | 100.00% |
Houston Electric | General Mortgage Bonds |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Secured debt |  |  | $ 8,000 |
General mortgage bonds used as collateral |  |  | $ 68 |
Percentage of property additions |  |  | 70.00% |
Additional first mortgage bonds and general mortgage bonds that could be issued |  |  | $ 4,600 |
Percentage of property additions (as a percent) |  |  | 70.00% |
Houston Electric | General Mortgage Bonds 5.15% Due 2034 | General Mortgage Bonds |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Debt instrument, face amount |  | $ 400 |  |
Debt instrument, interest rate, stated percentage |  | 5.15% |  |
Proceeds from issuance of long-term debt and capital securities, net |  | $ 395 |  |
SIGECO | First Mortgage Bonds |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Secured debt |  |  | $ 825 |
Additional first mortgage bonds and general mortgage bonds that could be issued |  |  | $ 966 |
Percentage of property additions (as a percent) |  |  | 70.00% |
Third Party AMAs |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Inventory financings |  |  | $ 0 | $ 4
Third Party AMAs | CERC |  |  |  |
Debt Instrument [Line Items] |  |  |  |
Inventory financings |  |  | $ 0 | $ 4

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