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Long-Term Debt - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
Mar. 31, 2015
Dec. 31, 2014
Apr. 10, 2015
Debt Instrument [Line Items]      
Long-term debt, carrying amount $ 3,627.7us-gaap_DebtInstrumentCarryingAmount $ 3,628.5us-gaap_DebtInstrumentCarryingAmount  
Estimated fair value 4,035.8us-gaap_LongTermDebtFairValue 3,987.8us-gaap_LongTermDebtFairValue  
TECO Finance [Member] | Floating Rate Notes Due 2018 [Member] | Subsequent Event [Member]      
Debt Instrument [Line Items]      
Aggregate principal amount issued     250us-gaap_DebtInstrumentFaceAmount
/ dei_LegalEntityAxis
= te_TecoFinanceMember
/ us-gaap_LongtermDebtTypeAxis
= te_FloatingRateNotesDueTwoThousandEighteenMember
/ us-gaap_SubsequentEventTypeAxis
= us-gaap_SubsequentEventMember
Tampa Electric Company [Member]      
Debt Instrument [Line Items]      
Long-term debt, carrying amount 2,097.1us-gaap_DebtInstrumentCarryingAmount
/ dei_LegalEntityAxis
= us-gaap_AffiliatedEntityMember		 2,097.1us-gaap_DebtInstrumentCarryingAmount
/ dei_LegalEntityAxis
= us-gaap_AffiliatedEntityMember		  
Estimated fair value $ 2,414.8us-gaap_LongTermDebtFairValue
/ dei_LegalEntityAxis
= us-gaap_AffiliatedEntityMember		 $ 2,372.2us-gaap_LongTermDebtFairValue
/ dei_LegalEntityAxis
= us-gaap_AffiliatedEntityMember