Short-Term Debt - Credit Facilities (Detail) (USD $)	Dec. 31, 2013	Dec. 17, 2013	Dec. 31, 2012
Line of Credit Facility [Line Items]
Credit Facilities	$ 675,000,000		$ 675,000,000
Borrowings Outstanding	84,000,000		0
Letters of Credit Outstanding	700,000		1,500,000
Tampa Electric Company [Member]
Line of Credit Facility [Line Items]
Credit Facilities	475,000,000	200,000,000	475,000,000
Borrowings Outstanding	84,000,000		0
Letters of Credit Outstanding	700,000		1,500,000
Tampa Electric Company [Member] | 5-year Facility [Member]
Line of Credit Facility [Line Items]
Credit Facilities	325,000,000		325,000,000
Borrowings Outstanding	6,000,000		0
Letters of Credit Outstanding	700,000		1,500,000
Tampa Electric Company [Member] | 1-year Accounts Receivable Facility [Member]
Line of Credit Facility [Line Items]
Credit Facilities	150,000,000		150,000,000
Borrowings Outstanding	78,000,000		0
Letters of Credit Outstanding	0		0
TECO Energy [Member] | 5-year Facility [Member]
Line of Credit Facility [Line Items]
Credit Facilities	200,000,000		200,000,000
Borrowings Outstanding	0		0
Letters of Credit Outstanding	$ 0		$ 0