Long-Term Debt - Schedule of Long-Term Debt Outstanding (Parenthetical) (Detail)	Dec. 31, 2012
Teco Energy [Member] | 6.75% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	6.75%
Effective interest rate	6.90%
Teco Finance [Member] | 6.75% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	6.75%
Effective interest rate	6.90%
Teco Finance [Member] | 4.00% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	4.00%
Effective interest rate	4.20%
Teco Finance [Member] | 6.752% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	6.572%
Effective interest rate	7.30%
Teco Finance [Member] | 5.15% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	5.15%
Effective interest rate	5.30%
Tampa Electric [Member] | 5.1% Refunding bonds [Member]
Debt Instrument [Line Items]
Stated interest rate	5.10%
Effective interest rate	5.60%
Tampa Electric [Member] | 5.65% Refunding bonds [Member]
Debt Instrument [Line Items]
Stated interest rate	5.65%
Effective interest rate	5.90%
Tampa Electric [Member] | 5.5% Refunding bonds [Member]
Debt Instrument [Line Items]
Stated interest rate	5.50%
Effective interest rate	6.20%
Tampa Electric [Member] | 5.15% Refunding bonds [Member]
Debt Instrument [Line Items]
Stated interest rate	5.15%
Effective interest rate	5.40%
Tampa Electric [Member] | 1.5% term rate bonds repurchased in 2011 [Member]
Debt Instrument [Line Items]
Stated interest rate	1.50%
Tampa Electric [Member] | 5.0% Refunding bonds [Member]
Debt Instrument [Line Items]
Stated interest rate	5.00%
Effective interest rate	5.80%
Tampa Electric [Member] | 6.875% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	6.875%
Effective interest rate	7.10%
Tampa Electric [Member] | 6.375% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	6.375%
Effective interest rate	7.90%
Tampa Electric [Member] | 6.25% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	6.25%
Effective interest rate	6.30%
Tampa Electric [Member] | 6.1% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	6.10%
Effective interest rate	6.40%
Tampa Electric [Member] | 5.4% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	5.40%
Effective interest rate	5.90%
Tampa Electric [Member] | 2.6% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	2.60%
Effective interest rate	2.70%
Tampa Electric [Member] | 6.55% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	6.55%
Effective interest rate	6.60%
Tampa Electric [Member] | 6.15% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	6.15%
Effective interest rate	6.20%
Tampa Electric [Member] | 4.1% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	4.10%
Effective interest rate	4.20%
PGS [Member] | 6.875% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	6.875%
Effective interest rate	7.10%
PGS [Member] | 6.375% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	6.375%
Effective interest rate	7.90%
PGS [Member] | 6.1% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	6.10%
Effective interest rate	7.00%
PGS [Member] | 5.4% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	5.40%
Effective interest rate	5.80%
PGS [Member] | 2.6% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	2.60%
Effective interest rate	2.70%
PGS [Member] | 6.15% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	6.15%
Effective interest rate	6.20%
PGS [Member] | 4.1% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	4.10%
Effective interest rate	4.20%
PGS [Member] | 8.00% Senior Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	8.00%
TECO Guatemala [Member] | 3.00% Notes [Member]
Debt Instrument [Line Items]
Stated interest rate	3.00%