Consolidated Statements of Capitalization - Capital Stock (Parenthetical) (Detail) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014
Preferred stock - par value	$ 1
Equity contributions made by TECO Energy	$ 175.0	$ 100.0
Preferred Stock Par Value [Member]
Preferred stock, shares authorized	10,000,000
Preferred stock, shares outstanding	0
Tampa Electric Company [Member]
Preferred stock - par value	$ 100
Preferred stock, no par value
Tampa Electric Company [Member] | Preferred Stock Par Value [Member]
Preferred stock, shares authorized	1,500,000
Preferred stock, shares outstanding	0
Tampa Electric Company [Member] | Preferred Stock No Par Value [Member]
Preferred stock, shares authorized	2,500,000
Preferred stock, shares outstanding	0
Tampa Electric Company [Member] | Preference Stock No Par Value [Member]
Preferred stock, no par value
Preferred stock, shares authorized	2,500,000
Preferred stock, shares outstanding	0