Regulatory - Additional Information (Detail)							1 Months Ended				3 Months Ended		9 Months Ended		12 Months Ended
	Sep. 28, 2022 USD ($)	Aug. 01, 2022 BTU	Jul. 01, 2022 USD ($)	Aug. 06, 2021 USD ($)	Nov. 19, 2020 USD ($)	Oct. 31, 2013 USD ($)	Jan. 31, 2024 USD ($)	Jan. 31, 2023 USD ($)	Sep. 30, 2022 USD ($)	Jan. 31, 2022 USD ($)	Dec. 31, 2022 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2022 USD ($)	Sep. 30, 2021 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)
Public Utilities General Disclosures [Line Items]
Base rate adjustment amount			$ 10,000,000
Changes in base rate under agreement														$ 0
Accumulated depreciation									$ 3,795,000,000			$ 3,795,000,000	$ 3,795,000,000		$ 3,601,000,000
Additional cost recovery from settlement agreement										$ 169,000,000
PGS and OPC [Member]
Public Utilities General Disclosures [Line Items]
Increase in revenue					$ 34,000,000
Allowed equity in the capital structure					54.70%
Accumulated depreciation					$ 34,000,000				34,000,000			34,000,000	34,000,000
Increase in annual base rate					58,000,000
PGS and OPC [Member] | Cast Iron and Bare Steel Replacement Rider [Member]
Public Utilities General Disclosures [Line Items]
Increase in revenue					$ 24,000,000
PGS [Member]
Public Utilities General Disclosures [Line Items]
Accumulated depreciation reversed amount												$ 4,000,000	$ 14,000,000
Settlement Agreement [Member]
Public Utilities General Disclosures [Line Items]
Settlement agreement, approval date				Aug. 06, 2021
Base rate adjustment amount				$ 123,000,000
Increase in revenue				$ 191,000,000
Settlement agreement number of subsequent years adjustments				2 years
Allowed equity in the capital structure				54.00%
Basis point increase applicable				25.00%
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	$ 90,000,000
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%
PGA change | BTU		1.19163
Minimum [Member] | PGS and OPC [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE					8.90%
Base rate agreement frozen period					Jan. 01, 2021
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%
PGA change | BTU		1.70492
Maximum [Member] | PGS and OPC [Member]
Public Utilities General Disclosures [Line Items]
Percentage of ROE					11.00%
Base rate agreement frozen period					Dec. 31, 2023
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%
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]
Settlement agreement recovery description													Tampa Electric’s Settlement Agreement provides recovery for the Big Bend modernization project in two phases. The first phase is a revenue increase to cover the costs of the assets in service during 2022, among other items. The remainder of the project costs will be recovered as part of the 2023 subsequent year adjustment.
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
Multiple Hurricanes [Member]
Public Utilities General Disclosures [Line Items]
Storm restoration preparation costs															$ 10,000,000	$ 10,000,000	$ 10,000,000
Hurricane Ian [Member]
Public Utilities General Disclosures [Line Items]
Restoration costs									130,000,000
Restoration costs incurred									68,000,000
Storm reserve expected to charge									$ 67,000,000		$ 59,000,000		$ 126,000,000
Storm restoration costs charged to reserve													10,000,000
Replenishment of balance in reserve						$ 136,000,000							$ 56,000,000
Hurricane Ian [Member] | Scenario Forecast [Member]
Public Utilities General Disclosures [Line Items]
Restoration costs incurred											$ 62,000,000
Hurricane Ian [Member] | Minimum [Member]
Public Utilities General Disclosures [Line Items]
Regulatory asset for future recovery	$ 1,000,000
Hurricane Ian [Member] | Maximum [Member]
Public Utilities General Disclosures [Line Items]
Restoration costs	$ 3,000,000