Consolidated Statements of Capitalization - Long-Term Debt - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2020	Dec. 31, 2019
Debt Instrument [Line Items]
Long-term debt, total	$ 2,903	$ 2,904
Unamortized debt discount, net	(10)	(10)
Debt issuance costs	(21)	(25)
Long-term debt, carrying amount	2,872	2,869
Less amount due within one year	278	0
Total long-term debt	2,594	2,869
Long-term debt, fair value	3,597	3,335
Tampa Electric [Member]
Debt Instrument [Line Items]
Long-term debt, total	2,566	2,567
Long-term debt, carrying amount	$ 2,566
Tampa Electric [Member] \| 5.40% Notes [Member]
Debt Instrument [Line Items]
Due	2021
Long-term debt, total	$ 231	232
Tampa Electric [Member] \| 2.60% Notes [Member]
Debt Instrument [Line Items]
Due	2022
Long-term debt, total	$ 225	225
Tampa Electric [Member] \| 6.55% Notes [Member]
Debt Instrument [Line Items]
Due	2036
Long-term debt, total	$ 250	250
Tampa Electric [Member] \| 6.15% Notes [Member]
Debt Instrument [Line Items]
Due	2037
Long-term debt, total	$ 190	190
Tampa Electric [Member] \| 4.10% Notes [Member]
Debt Instrument [Line Items]
Due	2042
Long-term debt, total	$ 250	250
Tampa Electric [Member] \| 4.35% Notes [Member]
Debt Instrument [Line Items]
Due	2044
Long-term debt, total	$ 290	290
Tampa Electric [Member] \| 4.20% Notes [Member]
Debt Instrument [Line Items]
Due	2045
Long-term debt, total	$ 230	230
Tampa Electric [Member] \| 4.30% Notes [Member]
Debt Instrument [Line Items]
Due	2048
Long-term debt, total	$ 275	275
Tampa Electric [Member] \| 4.45% Notes [Member]
Debt Instrument [Line Items]
Due	2049
Long-term debt, total	$ 350	350
Tampa Electric [Member] \| 3.63% Notes [Member]
Debt Instrument [Line Items]
Due	2050
Long-term debt, total	$ 275	275
PGS [Member]
Debt Instrument [Line Items]
Long-term debt, total	337	337
Long-term debt, carrying amount	$ 337
PGS [Member] \| 5.40% Notes [Member]
Debt Instrument [Line Items]
Due	2021
Long-term debt, total	$ 47	47
PGS [Member] \| 2.60% Notes [Member]
Debt Instrument [Line Items]
Due	2022
Long-term debt, total	$ 25	25
PGS [Member] \| 6.15% Notes [Member]
Debt Instrument [Line Items]
Due	2037
Long-term debt, total	$ 60	60
PGS [Member] \| 4.10% Notes [Member]
Debt Instrument [Line Items]
Due	2042
Long-term debt, total	$ 50	50
PGS [Member] \| 4.35% Notes [Member]
Debt Instrument [Line Items]
Due	2044
Long-term debt, total	$ 10	10
PGS [Member] \| 4.20% Notes [Member]
Debt Instrument [Line Items]
Due	2045
Long-term debt, total	$ 20	20
PGS [Member] \| 4.30% Notes [Member]
Debt Instrument [Line Items]
Due	2048
Long-term debt, total	$ 75	75
PGS [Member] \| 4.45% Notes [Member]
Debt Instrument [Line Items]
Due	2049
Long-term debt, total	$ 25	25
PGS [Member] \| 3.63% Notes [Member]
Debt Instrument [Line Items]
Due	2050
Long-term debt, total	$ 25	$ 25

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Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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