Preferred Stock - Additional Information (Detail) (USD $)	Dec. 31, 2012
Preferred Stock Par Value [Member)
Authorized Classes Of Cumulative Preferred And Preference Stocks [Line Items]
Preferred stock, par value	$ 1
Preferred stock, shares authorized	10,000,000
Preferred stock, shares outstanding	0
Preferred Stock Par Value [Member) | TAMPA ELECTRIC CO [Member]
Authorized Classes Of Cumulative Preferred And Preference Stocks [Line Items]
Preferred stock, par value	$ 100
Preferred stock, shares authorized	1,500,000
Preferred stock, shares outstanding	0
Preferred Stock No Par Value [Member] | TAMPA ELECTRIC CO [Member]
Authorized Classes Of Cumulative Preferred And Preference Stocks [Line Items]
Preferred stock, no par value	$ 0
Preferred stock, shares authorized	2,500,000
Preferred stock, shares outstanding	0
Preference Stock (Subordinated Preferred Stock) Of Tampa Electric - No Par [Member] | TAMPA ELECTRIC CO [Member]
Authorized Classes Of Cumulative Preferred And Preference Stocks [Line Items]
Preferred stock, no par value	$ 0
Preferred stock, shares authorized	2,500,000
Preferred stock, shares outstanding	0