Leases - Additional Information Related to Leases (Detail) - Tampa Electric [Member] - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2024	Dec. 31, 2023
Lessee, Lease, Description [Line Items]
Operating cash flows for operating leases (millions)	$ 5	$ 4
Weighted average remaining lease term (years)	46 years	45 years
Weighted average discount rate - operating leases	4.40%	4.40%

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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Amount of cash outflow from operating lease, excluding payments to bring another asset to condition and location necessary for its intended use.

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Weighted average discount rate for operating lease calculated at point in time.

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Weighted average remaining lease term for operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

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