Discontinued Operations - Components of Discontinued Operations (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income (loss) from discontinued operations	$ (0.2)	$ (10.6)	$ 33.3
Provision for income taxes	0.1	(22.4)	(11.2)
Income (loss) from discontinued operations, net	(0.1)	(33.0)	22.1
Less: Income from discontinued operations attributable to noncontrolling interest	0	0.3	0.3
Income (loss) from discontinued operations attributable to TECO Energy, net	(0.1)	(33.3)	21.8
TECO Guatemala [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Revenues	0	114.2	133.5
(Loss) income from operations	(0.2)	27.7	33.7
Loss on assets sold, including transaction costs	0	(38.3)	(0.4)
Income (loss) from discontinued operations	(0.2)	(10.6)	33.3
Provision for income taxes	(0.1)	22.4	11.2
Income (loss) from discontinued operations, net	(0.1)	(33.0)	22.1
Less: Income from discontinued operations attributable to noncontrolling interest	0	0.3	0.3
Income (loss) from discontinued operations attributable to TECO Energy, net	$ (0.1)	$ (33.3)	$ 21.8