Effect of base rate adjustment on revenue.

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Intervening party description.

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Minimum cost recovery period.

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Number of customers impacted by storm.

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Number of years worst weather event impact on area.

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- Definition

Replenishment reserve for recovery of cost.

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- Definition

Storm restoration costs.

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- Definition

Storm restoration costs charged to reserve.

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- Definition

Storm restoration preparation costs.

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- Definition

Percentage of public utility's approved equity to capital, including debt and equity.

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Percentage of public utility's approved return on equity.

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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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Period end book value of accumulated depreciation on property, plant and equipment (PPE) that is owned by the regulated operations of the public utility.

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- Definition

The amount for the individual regulatory asset as itemized in a table of regulatory assets as of the end of the period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 980
-SubTopic 340
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478742/980-340-50-1

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Regulatory - Additional Information (Detail) $ in Millions							6 Months Ended	12 Months Ended
Regulatory - Additional Information (Detail) $ in Millions	Jan. 31, 2027 USD ($)	Jan. 31, 2026 USD ($)	Feb. 04, 2025 USD ($)	Jan. 31, 2025 USD ($)	Dec. 03, 2024	Oct. 09, 2024 Customer	Jun. 30, 2025 USD ($)	Dec. 31, 2024 USD ($)	Sep. 26, 2024 Customer
Public Utilities General Disclosures [Line Items]
Intervening party description							On March 3, 2025, two intervening parties each filed a notice of appeal to the Florida Supreme Court regarding the outcome of Tampa Electric's 2024 base rate proceeding. As of August 8, 2025, the intervening parties have not filed their briefs related to the appeal
Accumulated depreciation							$ 3,516	$ 3,348
Storm restoration preparation costs							285	377
Regulatory asset for storm restoration costs							$ 1,376	$ 1,441
Settlement Agreement [Member]
Public Utilities General Disclosures [Line Items]
Allowed equity in the capital structure					54.00%
Minimum [Member] \| Settlement Agreement [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE				9.50%
Maximum [Member] \| Settlement Agreement [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE				11.50%
Mid Point [Member] \| Settlement Agreement [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE				10.50%
Storm Restoration Cost Recovery [Member]
Public Utilities General Disclosures [Line Items]
Minimum cost recovery period							12 months
Replenishment reserve for recovery of cost							$ 56
Tampa Electric Base Rates, on April 02, 2024 [Member]
Public Utilities General Disclosures [Line Items]
Effect of base rate adjustment on revenue				$ 297
Tampa Electric Base Rates, on April 02, 2024 [Member] \| Scenario Forecast [Member]
Public Utilities General Disclosures [Line Items]
Effect of base rate adjustment on revenue	$ 72	$ 100
Tampa Electric Base Rates on August 22, 2024 [Member] \| After FPSC Final Order [Member]
Public Utilities General Disclosures [Line Items]
Effect of base rate adjustment on revenue				$ 185
Tampa Electric Base Rates on August 22, 2024 [Member] \| After FPSC Final Order [Member] \| Scenario Forecast [Member]
Public Utilities General Disclosures [Line Items]
Effect of base rate adjustment on revenue	$ 9	$ 87
Hurricane Helene [Member]
Public Utilities General Disclosures [Line Items]
Storm restoration costs charged to reserve							48
Number of customers impacted by storm \| Customer									100,000
Hurricane Milton [Member]
Public Utilities General Disclosures [Line Items]
Storm restoration costs charged to reserve							340
Number of customers impacted by storm \| Customer						600,000
Number of years worst weather event impact on area						100 years
Hurricane Idalia Debby Helene and Milton [Member]
Public Utilities General Disclosures [Line Items]
Storm restoration costs			$ 466				$ 98