Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2012 TAMPA ELECTRIC CO [Member]	Dec. 31, 2011 TAMPA ELECTRIC CO [Member]	Dec. 31, 2010 TAMPA ELECTRIC CO [Member]
Cash flows from operating activities
Net income	$ 212.7	$ 272.6	$ 239.0	$ 227.2	$ 235.3	$ 242.9
Adjustments to reconcile net income to net cash from operating activities:
Depreciation and amortization	330.6	317.2	305.6	288.2	270.5	261.9
Deferred income taxes	136.9	146.0	162.9	155.9	173.6	70.4
Investment tax credits	(0.3)	(0.4)	(0.4)	(0.3)	(0.4)	(0.4)
Allowance for other funds used during construction	(2.6)	(1.0)	(1.9)	(2.6)	(1.0)	(1.9)
Non-cash stock compensation	12.0	9.1	7.4
Loss (gain) on sales of business/assets, pretax	35.7	(0.5)	(39.6)
Non-cash debt extinguishment/exchange, pretax	0	0	2.2
Equity in earnings of unconsolidated affiliates, net of cash distributions on earnings	0	0	6.9
Deferred recovery clauses	(8.9)	(9.0)	55.0	(8.9)	(9.0)	55.0
Receivables, less allowance for uncollectibles	37.7	5.7	(43.9)	1.6	47.8	(36.0)
Inventories	(2.4)	23.5	(41.4)	4.1	12.6	(36.5)
Prepayments and other current assets	(2.0)	(2.8)	(1.3)
Prepayments				(1.0)	(0.5)	2.0
Taxes accrued	12.1	(5.7)	4.9	(5.7)	7.9	(5.8)
Interest accrued	(5.9)	0.3	(6.0)	(8.3)	1.0	(3.1)
Accounts payable	(1.3)	(42.6)	51.0	12.4	(42.2)	36.6
Gain on sale of assets, pretax				(0.2)	(0.3)	(0.3)
Other	(4.7)	34.3	(43.3)	5.2	29.4	(31.9)
Cash flows from operating activities	756.7	754.1	664.4	667.6	724.7	552.9
Cash flows from investing activities
Capital expenditures	(505.1)	(454.1)	(489.7)	(459.0)	(386.8)	(393.6)
Allowance for other funds used during construction	2.6	1.0	1.9	2.6	1.0	1.9
Net proceeds from sales of business/assets	194.4	3.5	183.1
Net proceeds from sale of assets				0.3	2.8	0
Net cash increase from consolidation	0	0	24.1
Restricted cash	8.9	0	0
Contributions to unconsolidated affiliates	0	0	(1.7)
Other investing activities	0	14.4	(14.0)
Cash flows used in investing activities	(299.2)	(435.2)	(296.3)	(456.1)	(383.0)	(391.7)
Cash flows from financing activities
Dividends	(190.4)	(183.2)	(174.7)	(228.3)	(240.7)	(239.3)
Common stock	3.9	7.0	7.8	118.0	0	50.0
Proceeds from long-term debt issuance	538.1	0	661.2	538.1	0	73.0
Repayment of long-term debt/Purchase in lieu of redemption	(650.4)	(153.6)	(797.2)	(608.0)	(78.8)	(3.7)
Dividend to noncontrolling interest	(0.3)	(0.6)	(0.7)
Restricted cash	(1.9)	0	0
Net decrease in short-term debt	0	(12.0)	(43.0)	0	(12.0)	(43.0)
Cash flows used in financing activities	(301.0)	(342.4)	(346.6)	(180.2)	(331.5)	(163.0)
Net increase (decrease) in cash and cash equivalents	156.5	(23.5)	21.5	31.3	10.2	(1.8)
Cash and cash equivalents at beginning of the year	44.0	67.5	46.0	13.9	3.7	5.5
Cash and cash equivalents at end of the year	200.5	44.0	67.5	45.2	13.9	3.7
Supplemental disclosure of cash flow information
Interest	188.4	191.6	219.0	128.1	129.0	135.6
Income taxes	$ 7.2	$ 9.4	$ 5.5	$ (9.7)	$ (31.1)	$ 81.6