Regulatory - Additional Information (Detail) - USD ($)		1 Months Ended	12 Months Ended
	Feb. 01, 2012	Mar. 31, 2011	Dec. 31, 2015	Dec. 31, 2013	Dec. 31, 2014
Percentage of ROE			10.75%
Allowed equity in the capital structure			54.70%
Regulatory matters allowed rate base			$ 560,800,000
PGS Rates [Member]
Percentage of ROE			10.75%
Allowed equity in the capital structure			54.70%
Regulatory matters allowed rate base			$ 560,800,000
Minimum [Member]
Return on equity			9.75%
Minimum [Member] | PGS Rates [Member]
Return on equity			9.75%
Maximum [Member]
Return on equity			11.75%
Maximum [Member] | PGS Rates [Member]
Return on equity			11.75%
Tampa Electric Company [Member]
Higher Revenue Requirements			$ 104,000,000
Percentage of ROE			10.25%	11.25%
Allowed equity in the capital structure				54.00%
Period of average rate base				13 months
Revenue due to average rate base				$ 3,400,000,000
Increase in revenue by modification in base rate				33,500,000
Return on equity range			Range of plus or minus 1%
Potential increase in ROE			10.50%
Amortization period of Regulatory Asset			12 years
Annual accrual storm damage reserve				$ 8,000,000
Storm damage reserve			$ 56,100,000		$ 56,100,000
Storm damage cost recovery period			12-month period or longer
Application to increase base rate on normalized annual basis		$ 34,500,000
Increased Base Rate on Normalized Annual Basis	$ 21,500,000
Previous monthly residential access fee	9.59
Monthly residential customer access fee increased	$ 11.50
Tampa Electric Company [Member] | November 1, 2013 [Member]
Additional Revenue generated from increase in service charge			$ 57,500,000
Tampa Electric Company [Member] | November 1, 2014 [Member]
Additional Revenue generated from increase in service charge			7,500,000
Tampa Electric Company [Member] | November 1, 2015 [Member]
Additional Revenue generated from increase in service charge			5,000,000
Tampa Electric Company [Member] | January 1,2017 [Member]
Additional Revenue generated from increase in service charge			$ 110,000,000
Tampa Electric Company [Member] | Condition One [Member]
ROE lower range limit			9.25%
ROE upper range limit			11.25%
Tampa Electric Company [Member] | Condition Two [Member]
ROE lower range limit			9.50%
ROE upper range limit			11.50%
Tampa Electric Company [Member] | Computer Software [Member]
Amortization period of Regulatory Asset			15 years