Regulatory - Additional Information (Detail) (Tampa Electric Company [Member], USD $)	0 Months Ended	12 Months Ended
	Feb. 04, 2013	Dec. 31, 2013	Apr. 05, 2013	Dec. 31, 2012
Percentage of return on equity	11.25%	11.25%
Allowed equity in the capital structure		54.00%
Period of average base rate		13 months
Revenue due to average base rate		$ 3,400,000,000
Increase in revenue by modification in base rate		33,500,000
Additional Revenue generated from increase in service charge			134,800,000
Potential increase in ROE		10.25%
Return on equity range		Range of plus or minus 1%
Amortization period for computer software under regulatory requirement description		Tampa Electric will begin using a 15-year amortization period for all computer software
Annual accrual storm damage reserve		8,000,000
Storm damage reserve		56,100,000		50,400,000
Condition One [Member]
ROE lower range limit		11.25%
ROE upper range limit		9.25%
Condition Two [Member]
ROE lower range limit		11.50%
ROE upper range limit		9.50%
Transmission and Delivery Storm Reserve [Member]
Storm damage cost recovery period		12 months
November 1, 2013 [Member]
Additional Revenue generated from increase in service charge		57,500,000
November 1, 2014 [Member]
Additional Revenue generated from increase in service charge		7,500,000
November 1, 2015 [Member]
Additional Revenue generated from increase in service charge		5,000,000
January 1,2017 [Member]
Additional Revenue generated from increase in service charge		110,000,000
Maximum [Member]
Higher Revenue Requirements		$ 104,000,000
Return on equity	12.25%
Potential increase in ROE		10.50%
Minimum [Member]
Return on equity	10.25%