Significant Accounting Policies - Additional Information (Detail) - USD ($)			1 Months Ended	12 Months Ended
	Dec. 20, 2023	Jan. 01, 2023	Dec. 31, 2023	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jan. 30, 2024
Summary Of Significant Accounting Policies [Line Items]
Percentage of original cost of depreciable property				3.50%	3.20%	3.50%
Depreciation expense				$ 390,000,000	$ 402,000,000	$ 408,000,000
Allowance for funds used during construction rate				6.07%	6.00%	6.46%
Allowance for funds used during construction				$ 25,000,000	$ 46,000,000	$ 66,000,000
Receivables from contracts with customers			$ 284,000,000	284,000,000	295,000,000
Unbilled revenues			63,000,000	63,000,000	82,000,000
Franchise fees and gross receipts taxes				139,000,000	145,000,000	$ 129,000,000
Derivative Liabilities			$ 0	$ 0	$ 1,000,000
Derivative Liability, Statement of Financial Position [Extensible Enumeration]			Other Liabilities, Current	Other Liabilities, Current	Other Liabilities, Current
Derivative Assets			$ 1,000,000	$ 1,000,000	$ 5,000,000
Derivative Asset, Statement of Financial Position [Extensible Enumeration]			Prepaid Expense and Other Assets, Current	Prepaid Expense and Other Assets, Current	Prepaid Expense and Other Assets, Current
Issuance of common stock on transfer of assets		100
Gain (loss) from transaction		$ 0
Separation of PGS equity from TEC				$ (992,000,000)
Repayment of short term debt			$ 400,000,000
Common Stock [Member]
Summary Of Significant Accounting Policies [Line Items]
Separation of PGS equity from TEC				(871,000,000)
Retained Earnings [Member]
Summary Of Significant Accounting Policies [Line Items]
Separation of PGS equity from TEC				$ (121,000,000)
Term Loan [Member]
Summary Of Significant Accounting Policies [Line Items]
Principal amount		670,000,000
Repayment of short term debt	$ 670,000,000
Revolving Loan [Member]
Summary Of Significant Accounting Policies [Line Items]
Principal amount		$ 66,000,000
Repayment of short term debt	$ 286,000,000
Subsequent Event [Member]
Summary Of Significant Accounting Policies [Line Items]
Principal amount							$ 500,000,000
Minimum [Member]
Summary Of Significant Accounting Policies [Line Items]
Discount rates used in estimating other self-insurance liabilities				4.00%	4.00%
Maximum [Member]
Summary Of Significant Accounting Policies [Line Items]
Discount rates used in estimating other self-insurance liabilities				5.99%	5.78%
PGS [Member]
Summary Of Significant Accounting Policies [Line Items]
Allowance for funds used during construction rate					6.00%	6.00%
Tampa Electric [Member]
Summary Of Significant Accounting Policies [Line Items]
Depreciation expense				$ 390,000,000	$ 359,000,000	$ 357,000,000