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Amount of additional first mortgage bonds and general mortgage bonds that could be issued on the basis of retired bonds and 70% of property additions as of the balance sheet date.

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Percentage Of Property Additions

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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Percentage of principal amount of debt redeemed.

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Amount of cash inflow from long-term debt, finance lease obligation, and mandatorily redeemable capital security.

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Carrying value as of the balance sheet date, including the current and noncurrent portions, of collateralized debt obligations (with maturities initially due after one year or beyond the operating cycle, if longer). Such obligations include mortgage loans, chattel loans, and any other borrowings secured by assets of the borrower.

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Short-term Borrowings and Long-term Debt - Narrative (Details) - USD ($) $ in Millions		1 Months Ended
	Jan. 31, 2025	Mar. 31, 2025	Feb. 28, 2025
Medium Term Notes, Series F, Due 2028 \| CERC
Debt Instrument [Line Items]
Annual interest rate (as a percent)		6.36%
Principal amount repurchased		$ 10
Debt instrument, redemption price, percentage of principal amount redeemed		104.80%
SIGECO
Debt Instrument [Line Items]
Percentage of property additions (as a percent)		70.00%
Outstanding debt balance		$ 1,100
Additional debt issuable		899
SIGECO \| 5.69% First Mortgage Bonds, Series 2025A \| First Mortgage Bonds
Debt Instrument [Line Items]
Aggregate principal	$ 165
Annual interest rate (as a percent)	5.69%
Proceeds from issuance of long-term debt and capital securities, net	$ 164
Houston Electric
Debt Instrument [Line Items]
Additional first mortgage bonds and general mortgage bonds that could be issued		4,600
Houston Electric \| General Mortgage Bonds, 2.35% to 6.95%, Due 2026 to 2053
Debt Instrument [Line Items]
Secured debt		9,000
Houston Electric \| Bonds Pollution Control Due Range 1
Debt Instrument [Line Items]
Secured debt		$ 68
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]
Aggregate principal			$ 500
Annual interest rate (as a percent)			4.80%
Proceeds from issuance of long-term debt and capital securities, net			$ 495