Regulatory - Additional Information (Detail)												1 Months Ended					12 Months Ended
	Jan. 31, 2027 USD ($)	Jan. 31, 2026 USD ($)	Jan. 31, 2025 USD ($)	Nov. 09, 2023 USD ($)	Jan. 23, 2023 USD ($)	Jul. 01, 2022 USD ($)	Aug. 06, 2021 USD ($)	Aug. 03, 2021 USD ($)	Nov. 19, 2020 USD ($)	Oct. 31, 2013 USD ($)	Sep. 06, 2013	Jan. 31, 2024 USD ($)	Sep. 30, 2023 USD ($)	Jan. 31, 2023 USD ($)	Sep. 30, 2022 USD ($)	Jan. 31, 2022 USD ($)	Dec. 31, 2023 USD ($) Unit $ / kWh	Dec. 31, 2021 USD ($)	Dec. 31, 2019 USD ($)	Nov. 17, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2020 USD ($)
Public Utilities General Disclosures [Line Items]
Percentage of ROE																	10.25%
Return on equity range																	range of plus or minus 1%
Allowed equity in the capital structure											54.00%
Base rate adjustment amount						$ 10,000,000														$ 22,000,000
Changes in base rate under agreement																		$ 0
Utility plant, at original costs																	$ 13,655,000,000				$ 15,474,000,000
Accumulated depreciation																	$ 3,443,000,000				3,845,000,000
Number of units applied for recovery | Unit																	3
Adjustment to fuel and capacity charges recovery								$ 83,000,000
Adjustment to fuel and capacity charges recovery																$ 169,000,000
Adjustments to fuel charges recovery					$ 518,000,000
Adjustments to fuel charges recovery projected reduction					$ 170,000,000
Storm restoration preparation costs																			$ 10,000,000
Peoples Gas System [Member]
Public Utilities General Disclosures [Line Items]
Utility plant, at original costs																					2,938,000,000
Accumulated depreciation																					(687,000,000)
PGS and OPC [Member]
Public Utilities General Disclosures [Line Items]
Increase in revenue									$ 34,000,000
Accumulated depreciation									34,000,000								$ 34,000,000
Increase in annual base rate									58,000,000
Peoples Gas [Member]
Public Utilities General Disclosures [Line Items]
Accumulated depreciation reversed amount																	14,000,000
Hurricane Ian [Member]
Public Utilities General Disclosures [Line Items]
Storm Reserve Expected to Charge															$ 121,000,000
Storm restoration costs charged to reserve															10,000,000
Replenishment of balance in reserve										$ 131,000,000							56,000,000
Storm restoration costs															129,000,000
Storm restoration costs balance				$ 29,000,000
Hurricane Nicole [Member]
Public Utilities General Disclosures [Line Items]
Restoration costs															$ 2,000,000
Hurricane Idalia [Member]
Public Utilities General Disclosures [Line Items]
Storm restoration costs													$ 35,000,000
Electric Utility Plant [Member]
Public Utilities General Disclosures [Line Items]
Utility plant, at original costs																	$ 13,655,000,000				$ 12,536,000,000
Cast Iron and Bare Steel Replacement Rider [Member] | PGS and OPC [Member]
Public Utilities General Disclosures [Line Items]
Increase in revenue									$ 24,000,000
Scenario Forecast [Member]
Public Utilities General Disclosures [Line Items]
Effect of base rate adjustment on revenue	$ 70,000,000	$ 100,000,000
Settlement Agreement [Member]
Public Utilities General Disclosures [Line Items]
Settlement agreement, approval date							Aug. 06, 2021
Allowed equity in the capital structure							54.00%
Base rate adjustment amount							$ 123,000,000
Increase in revenue							$ 191,000,000
Settlement agreement number of subsequent years adjustments							2 years
Settlement agreement adjustment amount														$ 90,000,000
Basis point increase applicable							0.25%
Additional attainable revenue under settlement agreement							$ 10,000,000
Changes in base rate under agreement							$ 0
Impact of tax reform through reduction in base revenue days							180 days
Settlement Agreement [Member] | Scenario Forecast [Member]
Public Utilities General Disclosures [Line Items]
Settlement agreement adjustment amount												$ 21,000,000
Settlement Agreement [Member] | US Treasury Bond [Member]
Public Utilities General Disclosures [Line Items]
Calculating period							30 years
Determining period							6 months
Minimum [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE						9.25%
Minimum [Member] | PGS and OPC [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE									8.90%
Minimum [Member] | Hurricane Ian [Member]
Public Utilities General Disclosures [Line Items]
Storm restoration costs				129,000,000
Minimum [Member] | Scenario Forecast [Member]
Public Utilities General Disclosures [Line Items]
Effect of base rate adjustment on revenue			$ 290,000,000
Minimum [Member] | Settlement Agreement [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE							9.00%
Base rate agreement frozen period							Jan. 01, 2022
Minimum [Member] | Settlement Agreement [Member] | US Treasury Bond [Member]
Public Utilities General Disclosures [Line Items]
ROE revenue basis point on yield rate							0.50%
Maximum [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE						11.25%
Maximum [Member] | PGS and OPC [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE									11.00%
Maximum [Member] | Hurricane Ian [Member]
Public Utilities General Disclosures [Line Items]
Storm restoration costs				$ 134,000,000
Maximum [Member] | Scenario Forecast [Member]
Public Utilities General Disclosures [Line Items]
Effect of base rate adjustment on revenue			$ 320,000,000
Maximum [Member] | Settlement Agreement [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE							11.00%
Base rate agreement frozen period							Dec. 31, 2024
Mid Point [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE						10.20%
Mid Point [Member] | PGS and OPC [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE									9.90%
Mid Point [Member] | Settlement Agreement [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE							9.95%
Solar Project Cost Recovery [Member]
Public Utilities General Disclosures [Line Items]
Settlement agreement, extended terms																	four years through 2021
Settlement agreement, approval date																	Nov. 06, 2017
Cost cap of project | $ / kWh																	1,500
Cost savings benefit percentage for projects below cost cap																	75.00%
Solar generation capacity investments																	$ 850,000,000
Investments in gas reserves																	$ 0
Solar Project Cost Recovery [Member] | Minimum [Member]
Public Utilities General Disclosures [Line Items]
Solar project investment term																	2017
Solar Project Cost Recovery [Member] | Maximum [Member]
Public Utilities General Disclosures [Line Items]
Solar project investment term																	2021
Retiring Assets [Member] | Settlement Agreement [Member]
Public Utilities General Disclosures [Line Items]
Cost recovery from settlement agreement							$ 68,000,000
Retiring Coal Generation Units and Meter Assets [Member] | Settlement Agreement [Member]
Public Utilities General Disclosures [Line Items]
Settlement agreement cost recovery period							15 years
Big Bend Modernization Project [Member]
Public Utilities General Disclosures [Line Items]
Energy generation capacity investments																	$ 876,000,000
AFUDC included in energy project investment																	$ 91,000,000
Accumulated depreciation																						$ 267,000,000
Settlement agreement recovery description																	Tampa Electric’s Settlement Agreement provided recovery for the Big Bend modernization project in two phases. The first phase was a revenue increase to cover the costs of the assets in service during 2022, among other items. The remainder of the project costs was recovered as part of the 2023 subsequent year adjustment.
Big Bend Modernization Project [Member] | Electric Utility Plant [Member]
Public Utilities General Disclosures [Line Items]
Utility plant, at original costs																						$ 636,000,000
Big Bend Modernization Project [Member] | Minimum [Member]
Public Utilities General Disclosures [Line Items]
Energy project investment term																	2018
Big Bend Modernization Project [Member] | Maximum [Member]
Public Utilities General Disclosures [Line Items]
Energy project investment term																	2022
Big Bend Coal Generation Assets [Member]
Public Utilities General Disclosures [Line Items]
Settlement agreement cost recovery period																	15 years
Storm Restoration Cost Recovery [Member]
Public Utilities General Disclosures [Line Items]
Minimum cost recovery period																	12 months
Replenishment reserve for recovery of cost																	$ 56,000,000