Tampa Electric 10-Q31 Oct 142014 Q3 Quarterly reportFinancial data

Company Profile

Document_and_Entity_Informatio

Document and Entity Information	9 Months Ended
Document and Entity Information	Sep. 30, 2014	Oct. 27, 2014
Document Information [Line Items]	'	'
Document Type	'10-Q	'
Amendment Flag	'false	'
Document Period End Date	30-Sep-14	'
Document Fiscal Year Focus	'2014	'
Document Fiscal Period Focus	'Q3	'
Trading Symbol	'TE	'
Entity Registrant Name	'TECO ENERGY INC	'
Entity Central Index Key	'0000350563	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Large Accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	234,692,300
Tampa Electric Company [Member]	'	'
Document Information [Line Items]	'	'
Entity Registrant Name	'TAMPA ELECTRIC COMPANY	'
Entity Central Index Key	'0000096271	'
Current Fiscal Year End Date	'--12-31	'
Entity Filer Category	'Non-accelerated Filer	'
Entity Common Stock, Shares Outstanding	'	10

Consolidated_Condensed_Balance

Consolidated Condensed Balance Sheets (Unaudited) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Current assets	'	'
Cash and cash equivalents	$72.70	$185.20
Receivables, less allowance for uncollectibles	293	287.2
Inventories, at average cost	'	'
Derivative assets	0.2	9.7
Regulatory assets	24.3	34.3
Deferred income taxes	93.6	100.3
Prepayments and other current assets	29.6	34.9
Income tax receivables	0.8	1.5
Assets held for sale	133.7	0
Total current assets	815.2	857.7
Property, plant and equipment	'	'
Construction work in progress	545.7	386.7
Other property	14.3	448.3
Property, plant and equipment, at original costs	9,540.40	9,077.30
Accumulated depreciation	-2,588	-2,907.20
Total property, plant and equipment, net	6,952.40	6,170.10
Other assets	'	'
Regulatory assets	342.2	293.1
Goodwill	401.8	0
Derivative assets	0	0.3
Deferred charges and other assets	63.4	126.8
Assets held for sale	78.6	0
Total other assets	886	420.2
Total assets	8,653.60	7,448
Current liabilities	'	'
Long-term debt due within one year	274.5	83.3
Notes payable	72	84
Accounts payable	231.4	261.7
Customer deposits	174.9	164.5
Regulatory liabilities	65.8	85.8
Derivative liabilities	4.1	0.1
Interest accrued	60.3	31.9
Taxes accrued	76.6	34.6
Other	17.6	19.5
Liabilities associated with assets held for sale	41.1	0
Total current liabilities	1,018.30	765.4
Other liabilities	'	'
Deferred income taxes	510.8	444
Investment tax credits	9.1	9.4
Regulatory liabilities	727.2	631.4
Derivative liabilities	1.6	0.2
Deferred credits and other liabilities	364.6	426.1
Liabilities associated with assets held for sale	64.4	0
Long-term debt, less amount due within one year	3,354.80	2,837.80
Total other liabilities	5,032.50	4,348.90
Commitments and contingencies (see Note 10)	'	'
Capital	'	'
Common equity	234.6	217.3
Additional paid in capital	1,867.90	1,581.30
Retained earnings	520.4	548.3
Accumulated other comprehensive loss	-20.1	-13.2
Total capital	2,602.80	2,333.70
Long-term debt	3,354.80	2,837.80
Total liabilities and capital	8,653.60	7,448
Tampa Electric Company [Member]	'	'
Current assets	'	'
Cash and cash equivalents	59.1	9.8
Receivables, less allowance for uncollectibles	266.8	227.6
Inventories, at average cost	'	'
Derivative assets	0.1	9.5
Regulatory assets	22.9	34.3
Deferred income taxes	23.8	29.4
Prepayments and other current assets	24.9	12.5
Income tax receivables	0	54.9
Total current assets	550.1	548.5
Property, plant and equipment	'	'
Construction work in progress	528.2	385.3
Property, plant and equipment, at original costs	8,844.80	8,568.80
Accumulated depreciation	-2,582.10	-2,562.60
Total property, plant and equipment, net	6,271.10	6,014.50
Public Utilities, Property, Plant and Equipment, Net	6,262.70	6,006.20
Other property	8.4	8.3
Other assets	'	'
Regulatory assets	311.7	293.1
Derivative assets	0	0.3
Deferred charges and other assets	333.1	312.8
Unamortized debt expense	17.1	14.8
Other	4.3	4.6
Total assets	7,154.30	6,875.80
Current liabilities	'	'
Long-term debt due within one year	83.3	83.3
Notes payable	0	84
Accounts payable	210.3	226
Customer deposits	169.2	164.5
Regulatory liabilities	64.5	85.8
Derivative liabilities	4	0
Interest accrued	40.7	16.4
Taxes accrued	70.6	12.2
Other	11.9	12
Total current liabilities	654.5	684.2
Other liabilities	'	'
Deferred income taxes	1,165.20	1,114.30
Investment tax credits	9.1	9.4
Regulatory liabilities	623.5	631.4
Derivative liabilities	1.6	0.2
Long-term debt, less amount due within one year	2,013.80	1,797.50
Total other liabilities	2,091.10	2,063.40
Other	291.7	308.1
Commitments and contingencies (see Note 10)	'	'
Capital	'	'
Common equity	2,049.90	2,030.40
Retained earnings	352.3	308.1
Accumulated other comprehensive loss	-7.3	-7.8
Total capital	2,394.90	2,330.70
Long-term debt	2,013.80	1,797.50
Total capitalization	4,408.70	4,128.20
Total liabilities and capital	7,154.30	6,875.80
Fuel [Member]	'	'
Inventories, at average cost	'	'
Utility inventories	92.3	118.7
Fuel [Member] \| Tampa Electric Company [Member]	'	'
Inventories, at average cost	'	'
Utility inventories	80.9	93.7
Materials and Supplies [Member]	'	'
Inventories, at average cost	'	'
Utility inventories	75	85.9
Materials and Supplies [Member] \| Tampa Electric Company [Member]	'	'
Inventories, at average cost	'	'
Utility inventories	71.6	76.8
Electric [Member]	'	'
Property, plant and equipment	'	'
Public utilities, property, plant and equipment	7,029.90	6,934
Electric [Member] \| Tampa Electric Company [Member]	'	'
Property, plant and equipment	'	'
Public utilities, property, plant and equipment	7,029.90	6,934
Gas [Member]	'	'
Property, plant and equipment	'	'
Public utilities, property, plant and equipment	1,950.50	1,308.30
Gas [Member] \| Tampa Electric Company [Member]	'	'
Property, plant and equipment	'	'
Public utilities, property, plant and equipment	$1,286.70	$1,249.50

Consolidated_Condensed_Balance1

Consolidated Condensed Balance Sheets (Unaudited) (Parenthetical) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Allowance for uncollectibles	$2.50	$4.70
Common equity, shares authorized	400	400
Common equity, par value	$1	$1
Common equity, shares outstanding	234.6	217.3
Tampa Electric Company [Member]	'	'
Allowance for uncollectibles	$2.30	$2

Consolidated_Condensed_Stateme

Consolidated Condensed Statements of Income (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Revenues	'	'	'	'
Regulated electric and gas	$685.10	$639.60	$1,864.40	$1,782.70
Unregulated	2.1	2.5	6.5	10.2
Total revenues	687.2	642.1	1,870.90	1,792.90
Expenses	'	'	'	'
Fuel	204.5	202.8	523.8	517.3
Purchased power	21	15.7	59.1	50.8
Cost of natural gas sold	34.3	26.7	110.5	116.9
Other	137.9	127	385.3	377.4
Operation and maintenance other expense	14.8	3.5	22.6	8.2
Depreciation and amortization	78.6	76.1	230	222.8
Taxes, other than income	50.4	48.6	146.3	139.9
Total expenses	541.5	500.4	1,477.60	1,433.30
Income from continuing operations	145.7	141.7	393.3	359.6
Other income	'	'	'	'
Allowance for other funds used during construction	2.9	1.8	7.3	4.3
Other income	1	-0.4	-0.4	2.4
Total other income	3.9	1.4	6.9	6.7
Interest charges	'	'	'	'
Interest expense	44.4	40.9	126.8	124.1
Allowance for borrowed funds used during construction	-1.5	-1	-3.6	-2.5
Total interest charges	42.9	39.9	123.2	121.6
Income from continuing operations before provision for income taxes	106.7	103.2	277	244.7
Provision for income taxes	33.7	38.9	98	91.4
Net income from continuing operations	73	64.3	179	153.3
Discontinued operations	'	'	'	'
Loss from discontinued operations	-98.8	-2.9	-97.6	0
Benefit from income taxes	-36.9	-1.4	-38.2	-2.4
Loss on discontinued operations, net	-61.9	-1.5	-59.4	2.4
Net income	$11.10	$62.80	$119.60	$155.70
Average common shares outstanding - Basic	227.8	215.2	220.3	214.9
Average common shares outstanding - Diluted	228.3	215.6	220.8	215.4
Earnings per share from continuing operations - Basic	$0.32	$0.30	$0.81	$0.71
Earnings per share from continuing operations - Diluted	$0.32	$0.30	$0.81	$0.71
Earnings per share from discontinued operations - Basic	($0.28)	($0.01)	($0.27)	$0.01
Earnings per share from discontinued operations - Diluted	($0.28)	($0.01)	($0.27)	$0.01
Earnings per share - Basic	$0.04	$0.29	$0.54	$0.72
Earnings per share - Diluted	$0.04	$0.29	$0.54	$0.72
Dividends paid per common share outstanding	$0.22	$0.22	$0.66	$0.66

Consolidated_Condensed_Stateme1

Consolidated Condensed Statements of Income (Unaudited) (Parenthetical) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Statement [Abstract]	'	'	'	'
Franchise fees and gross receipts taxes	$31.70	$29.70	$86.70	$81.80

Consolidated_Condensed_Stateme2

Consolidated Condensed Statements of Comprehensive Income (Unaudited) (USD $)	3 Months Ended				9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013
Statement Of Income And Comprehensive Income [Abstract]	'		'		'		'
Net income	$11.10		$62.80		$119.60		$155.70
Other comprehensive income, net of tax	'		'		'		'
Net unrealized gains on cash flow hedges	0.1		0.8		0.4		1.1
Amortization of unrecognized benefit costs	0.2	[1]	0.6	[1]	1.6	[1]	2	[1]
Change in benefit obligation due to remeasurement	-0.7		0		-0.7		0
Increase in unrecognized postemployment costs	0		0		-8.2		0
Recognized benefit costs due to settlement	0		1.6		0		1.6
Other comprehensive income (loss), net of tax	($0.40)		$3		($6.90)		$4.70

[1]	Related to postretirement and postemployment benefits. See Note 5 for additional information

Consolidated_Condensed_Stateme3

Consolidated Condensed Statements of Cash Flows (Unaudited) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013
Cash flows from operating activities	'	'
Net income	$119.60	$155.70
Adjustments to reconcile net income to net cash from operating activities:	'	'
Depreciation and amortization	255.7	251.3
Deferred income taxes	58.7	89.1
Investment tax credits	-0.3	-0.3
Allowance for other funds used during construction	-7.3	-4.3
Non-cash stock compensation	10.2	10.2
Gain on sales of business/assets	-0.2	-0.3
Deferred recovery clauses	-5.5	-3.8
Asset impairment	98.4	0
Receivables, less allowance for uncollectibles	-25.9	-64.4
Inventories	-9.6	3.1
Prepayments and other current assets	-5.5	-4.2
Taxes accrued	48.6	44
Interest accrued	27.8	22.2
Accounts payable	-29.4	10.6
Other	-29.1	-2.8
Depreciation and amortization	230	222.8
Allowance for other funds used during construction	-7.3	-4.3
Cash flows from operating activities	506.2	506.1
Cash flows from investing activities	'	'
Capital expenditures	-491.8	-370.9
Allowance for other funds used during construction	7.3	4.3
Purchase of NMGI, net of cash acquired	-752.5	0
Net proceeds from sales of assets	0.3	0.4
Cash flows used in investing activities	-1,236.70	-366.2
Cash flows from financing activities	'	'
Dividends	-147.5	-143.4
Common stock	296.6	7.4
Proceeds from long-term debt issuance	564.2	0
Repayment of long-term debt/Purchase in lieu of redemption	-83.3	-51.6
Net decrease in short-term debt	-12	0
Cash flows from (used) in financing activities	618	-187.6
Net decrease in cash and cash equivalents	-112.5	-47.7
Cash and cash equivalents at beginning of the period	185.2	200.5
Cash and cash equivalents at end of the period	72.7	152.8
Supplemental disclosure of non-cash activities	'	'
Debt assumed in NMGI acquisition	200	0
Capital expenditures accrued-excluded above	10.2	-0.6
Tampa Electric Company [Member]	'	'
Cash flows from operating activities	'	'
Net income	214	178.2
Adjustments to reconcile net income to net cash from operating activities:	'	'
Deferred income taxes	50.4	57.7
Investment tax credits	-0.3	-0.3
Allowance for other funds used during construction	-7.3	-4.3
Deferred recovery clauses	-6	-3.8
Receivables, less allowance for uncollectibles	-39.2	-61.5
Inventories	18	-2.6
Prepayments	-6.6	-5.1
Taxes accrued	113.3	89.6
Interest accrued	24.3	20
Accounts payable	-24.1	6.2
Other	-23.3	1.4
Depreciation and amortization	225.9	221.6
Allowance for other funds used during construction	-7.3	-4.3
Cash flows from operating activities	539.1	497.1
Cash flows from investing activities	'	'
Capital expenditures	-475.8	-353.1
Allowance for other funds used during construction	7.3	4.3
Cash flows used in investing activities	-468.5	-348.8
Cash flows from financing activities	'	'
Dividends	-169.8	-147.6
Common stock	19.5	20
Proceeds from long-term debt issuance	296.3	0
Repayment of long-term debt/Purchase in lieu of redemption	-83.3	-51.6
Net decrease in short-term debt	-84	0
Cash flows from (used) in financing activities	-21.3	-179.2
Net decrease in cash and cash equivalents	49.3	-30.9
Cash and cash equivalents at beginning of the period	9.8	45.2
Cash and cash equivalents at end of the period	59.1	14.3
Supplemental disclosure of non-cash activities	'	'
Capital expenditures accrued-excluded above	$11	($0.60)

Consolidated_Condensed_Stateme4

Consolidated Condensed Statements of Income and Comprehensive Income (Unaudited) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Revenues	'	'	'	'
Total revenues	$687.20	$642.10	$1,870.90	$1,792.90
Expenses	'	'	'	'
Fuel	204.5	202.8	523.8	517.3
Purchased power	21	15.7	59.1	50.8
Cost of natural gas sold	34.3	26.7	110.5	116.9
Other	137.9	127	385.3	377.4
Depreciation and amortization	78.6	76.1	230	222.8
Taxes, other than income	50.4	48.6	146.3	139.9
Total expenses	541.5	500.4	1,477.60	1,433.30
Income from continuing operations	145.7	141.7	393.3	359.6
Other income	'	'	'	'
Allowance for other funds used during construction	2.9	1.8	7.3	4.3
Other income	1	-0.4	-0.4	2.4
Total other income	3.9	1.4	6.9	6.7
Interest charges	'	'	'	'
Interest expense	44.4	40.9	126.8	124.1
Allowance for borrowed funds used during construction	-1.5	-1	-3.6	-2.5
Total interest charges	42.9	39.9	123.2	121.6
Income from continuing operations before provision for income taxes	106.7	103.2	277	244.7
Provision for income taxes	33.7	38.9	98	91.4
Net income	11.1	62.8	119.6	155.7
Other comprehensive income, net of tax	'	'	'	'
Total other comprehensive income, net of tax	-0.4	3	-6.9	4.7
Tampa Electric Company [Member]	'	'	'	'
Revenues	'	'	'	'
Electric (includes franchise fees and gross receipts taxes of $27.4 in 2014 and $25.6 in 2013)	581.6	556.3	1,547.30	1,477
Gas (includes franchise fees and gross receipts taxes of $4.3 in 2014 and $4.1 in 2013)	86.9	83.1	300	306.3
Total revenues	668.5	639.4	1,847.30	1,783.30
Expenses	'	'	'	'
Fuel	204.5	202.8	523.8	517.3
Purchased power	21	15.7	59.1	50.8
Cost of natural gas sold	28.4	27	104.6	117.4
Other	130.9	126.8	378	376.9
Depreciation and amortization	75.4	75.6	225.9	221.6
Taxes, other than income	49.1	48.2	144.1	138.5
Total expenses	509.3	496.1	1,435.50	1,422.50
Income from continuing operations	159.2	143.3	411.8	360.8
Other income	'	'	'	'
Allowance for other funds used during construction	2.9	1.8	7.3	4.3
Other income	1.2	1.3	3.5	3.8
Total other income	4.1	3.1	10.8	8.1
Interest charges	'	'	'	'
Interest expense	27.7	26.3	79.8	79.2
Other interest	1	1	3.1	2.9
Allowance for borrowed funds used during construction	-1.4	-1.1	-3.5	-2.5
Total interest charges	27.3	26.2	79.4	79.6
Income from continuing operations before provision for income taxes	136	120.2	343.2	289.3
Provision for income taxes	51.5	46.1	129.2	111.1
Net income	84.5	74.1	214	178.2
Other comprehensive income, net of tax	'	'	'	'
Amortization of settled interest rate swaps	0.3	0.2	0.5	0.7
Total other comprehensive income, net of tax	0.3	0.2	0.5	0.7
Comprehensive income	$84.80	$74.30	$214.50	$178.90

Consolidated_Condensed_Stateme5

Consolidated Condensed Statements of Income and Comprehensive Income (Unaudited) (Parenthetical) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Franchise fees and gross receipts taxes	$31.70	$29.70	$86.70	$81.80
Tampa Electric Company [Member]	'	'	'	'
Franchise fees and gross receipts taxes	31.7	29.7	86.7	81.8
Tampa Electric Company [Member] \| Electric [Member]	'	'	'	'
Franchise fees and gross receipts taxes	27.4	25.6	70.4	66.1
Tampa Electric Company [Member] \| Gas [Member]	'	'	'	'
Franchise fees and gross receipts taxes	$4.30	$4.10	$16.30	$15.70

Summary_of_Significant_Account

Summary of Significant Accounting Policies	9 Months Ended
Summary of Significant Accounting Policies	Sep. 30, 2014
Summary of Significant Accounting Policies	'
	1. Summary of Significant Accounting Policies
	See TECO Energy, Inc.’s 2013 Annual Report on Form 10-K for a complete detailed discussion of accounting policies. The significant accounting policies for recently acquired NMGI and NMGC (see Note 16) are in alignment with TECO Energy, Inc.’s policies. The significant accounting policies for all utility and diversified operations include:
	Principles of Consolidation and Basis of Presentation
	All significant intercompany balances and intercompany transactions have been eliminated in consolidation. In the opinion of management, the unaudited consolidated condensed financial statements include all adjustments that are of a recurring nature and necessary to state fairly the financial position of TECO Energy, Inc. and its subsidiaries as of Sept. 30, 2014 and Dec. 31, 2013, and the results of operations and cash flows for the periods ended Sept. 30, 2014 and 2013. The results of operations for the three months and nine months ended Sept. 30, 2014 are not necessarily indicative of the results that can be expected for the entire fiscal year ending Dec. 31, 2014.
	The unaudited consolidated condensed financial statements include NMGI and NMGC as of the acquisition date of Sept. 2, 2014 (see Note 16). In addition, all periods have been adjusted to reflect the reclassification of results from operations to discontinued operations for TECO Coal and certain charges at Parent that directly related to TECO Coal (see Note 15).
	The use of estimates is inherent in the preparation of financial statements in accordance with U.S. GAAP. Actual results could differ from these estimates. The year-end consolidated condensed balance sheet data was derived from audited financial statements, however, this quarterly report on Form 10-Q does not include all year-end disclosures required for an annual report on Form 10-K by U.S. GAAP.
	Revenues
	As of Sept. 30, 2014 and Dec. 31, 2013, unbilled revenues of $61.0 million and $46.7 million, respectively, are included in the “Receivables” line item on the Consolidated Condensed Balance Sheets.
	Accounting for Excise Taxes, Franchise Fees and Gross Receipts
	TECO Coal incurs most of TECO Energy’s total excise taxes, which are accrued as an expense and reconciled to the actual cash payment of excise taxes. As general expenses, they are not specifically recovered through revenues. Excise taxes paid by the regulated utilities are not material and are expensed when incurred.
	Tampa Electric and PGS are allowed to recover certain costs on a dollar-per-dollar basis incurred from customers through prices approved by the FPSC. The amounts included in customers’ bills for franchise fees and gross receipt taxes are included as revenues on the Consolidated Condensed Statements of Income. Franchise fees and gross receipt taxes payable by the regulated utilities are included as an expense on the Consolidated Condensed Statements of Income in “Taxes, other than income”. These amounts totaled $31.7 million and $86.7 million, respectively, for the three and nine months ended Sept. 30, 2014, compared to $29.7 million and $81.8 million, respectively, for the three and nine months ended Sept. 30, 2013.
	Cash Flows Related to Derivatives and Hedging Activities
	The company classifies cash inflows and outflows related to derivative and hedging instruments in the appropriate cash flow sections associated with the item being hedged. In the case of diesel fuel swaps, which are used to mitigate the fluctuations in the price of diesel fuel, the cash inflows and outflows are included in the operating section. For natural gas and ongoing interest rate swaps, the cash inflows and outflows are included in the operating section. For interest rate swaps that settle coincident with the debt issuance, the cash inflows and outflows are treated as premiums or discounts and included in the financing section of the Consolidated Condensed Statements of Cash Flows.
	Goodwill
	Goodwill represents the excess of the purchase price over the value assigned to the net identifiable assets of businesses acquired. Accounting guidance requires that the company perform impairment tests on its goodwill annually or at any time when events occur that could impact the value of the company’s goodwill. If an impairment test of goodwill shows that the carrying amount of the goodwill is in excess of the fair value, a corresponding impairment loss would be recorded in the Statements of Operations. The company added goodwill during the quarter resulting from the NMGC acquisition (see Note 16).


Tampa Electric Company [Member]	'
Summary of Significant Accounting Policies	'
	1. Summary of Significant Accounting Policies
	See TEC’s 2013 Annual Report on Form 10-K for a complete detailed discussion of accounting policies. The significant accounting policies for TEC include:
	Principles of Consolidation and Basis of Presentation
	TEC is a wholly-owned subsidiary of TECO Energy, Inc. For the purposes of its consolidated financial reporting, TEC is comprised of the electric division, generally referred to as Tampa Electric, the natural gas division, generally referred to as PGS, and potentially the accounts of VIEs for which it is the primary beneficiary. For the periods presented, no VIEs have been consolidated (see Note 13).
	All significant intercompany balances and intercompany transactions have been eliminated in consolidation. In the opinion of management, the unaudited consolidated condensed financial statements include all adjustments that are of a recurring nature and necessary to state fairly the financial position of TEC as of Sept. 30, 2014 and Dec. 31, 2013, and the results of operations and cash flows for the periods ended Sept. 30, 2014 and 2013. The results of operations for the three and nine months ended Sept. 30, 2014 are not necessarily indicative of the results that can be expected for the entire fiscal year ending Dec. 31, 2014.
	The use of estimates is inherent in the preparation of financial statements in accordance with U.S. GAAP. Actual results could differ from these estimates. The year-end consolidated condensed balance sheet data was derived from audited financial statements, however, this quarterly report on Form 10-Q does not include all year-end disclosures required for an annual report on Form 10-K by U.S. GAAP.
	Revenues
	As of Sept. 30, 2014 and Dec. 31, 2013, unbilled revenues of $53.3 million and $46.7 million, respectively, are included in the “Receivables” line item on the Consolidated Condensed Balance Sheets.
	Accounting for Excise Taxes, Franchise Fees and Gross Receipts
	The regulated utilities are allowed to recover certain costs on a dollar-per-dollar basis incurred from customers through prices approved by the FPSC. The amounts included in customers’ bills for franchise fees and gross receipt taxes are included as revenues on the Consolidated Condensed Statements of Income. Franchise fees and gross receipt taxes payable by the regulated utilities are included as an expense on the Consolidated Condensed Statements of Income in “Taxes, other than income”. These amounts totaled $31.7 million and $86.7 million, respectively, for the three and nine months ended Sept. 30, 2014, compared to $29.7 million and $81.8 million, respectively, for the three and nine months ended Sept. 30, 2013.
	Cash Flows Related to Derivatives and Hedging Activities
	TEC classifies cash inflows and outflows related to derivative and hedging instruments in the appropriate cash flow sections associated with the item being hedged. For natural gas and ongoing interest rate swaps, the cash inflows and outflows are included in the operating section. For interest rate swaps that settle coincident with the debt issuance, the cash inflows and outflows are treated as premiums or discounts and included in the financing section of the Consolidated Condensed Statements of Cash Flows.

New_Accounting_Pronouncements

New Accounting Pronouncements	9 Months Ended
New Accounting Pronouncements	Sep. 30, 2014
New Accounting Pronouncements	'
	2. New Accounting Pronouncements
	Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity
	In April 2014, the FASB issued guidance regarding changing the criteria for reporting discontinued operations and enhancing convergence of the FASB’s and the IASB’s reporting requirements for discontinued operations. A disposal of a component of an entity or a group of components of an entity is required to be reported in discontinued operations if the disposal represents a strategic shift that has (or will have) a major effect on an entity’s operations and financial results. This standard is effective for the company beginning in 2015.
	Revenue from Contracts with Customers
	In May 2014, the FASB issued guidance regarding the accounting for revenue from contracts with customers. The standard is principle-based and provides a five-step model to determine when and how revenue is recognized. The core principle is that a company should recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. This guidance is effective for the company beginning in 2017 and allows for either full retrospective adoption or modified retrospective adoption. The company is currently evaluating the impact of the adoption of this guidance on its financial statements but does not expect the impact to be significant.
	Going Concern
	In August 2014, the FASB issued guidance defining management’s responsibility to decide whether there is substantial doubt about an organization’s ability to continue as a going concern and the related footnote disclosures required. This guidance is effective for the company beginning in 2017. The company does not expect any significant impact from the adoption of this guidance on its financial statements.
Tampa Electric Company [Member]	'
New Accounting Pronouncements	'
	2. New Accounting Pronouncements
	Reporting Discontinued Operations and Disclosures of Disposals of Components of an Entity
	In April 2014, the FASB issued guidance regarding changing the criteria for reporting discontinued operations and enhancing convergence of the FASB’s and the IASB’s reporting requirements for discontinued operations. A disposal of a component of an entity or a group of components of an entity is required to be reported in discontinued operations if the disposal represents a strategic shift that has (or will have) a major effect on an entity’s operations and financial results. This standard is effective for TEC beginning in 2015.
	Revenue from Contracts with Customers
	In May 2014, the FASB issued guidance regarding the accounting for revenue from contracts with customers. The standard is principle-based and provides a five-step model to determine when and how revenue is recognized. The core principle is that a company should recognize revenue when it transfers promised goods or services to customers in an amount that reflects the consideration to which the company expects to be entitled in exchange for those goods or services. This guidance is effective for TEC beginning in 2017 and allows for either full retrospective adoption or modified retrospective adoption. TEC is currently evaluating the impact of the adoption of this guidance on its financial statements but does not expect the impact to be significant.
	Going Concern
	In August 2014, the FASB issued guidance defining management’s responsibility to decide whether there is substantial doubt about an organization’s ability to continue as a going concern and the related footnote disclosures required. This guidance is effective for TEC beginning in 2017. The company does not expect any significant impact from the adoption of this guidance on its financial statements.

Regulatory

Regulatory	9 Months Ended
Regulatory	Sep. 30, 2014
Regulatory	'
	3. Regulatory
	Tampa Electric’s retail business and PGS are subject to regulation by the FPSC. Tampa Electric is also subject to regulation by the FERC under PUHCA 2005. However, pursuant to a waiver granted in accordance with the FERC’s regulations, TECO Energy is not subject to certain accounting, record-keeping and reporting requirements prescribed by the FERC’s regulations under PUHCA 2005. The operations of PGS are regulated by the FPSC separately from the operations of Tampa Electric. The FPSC has jurisdiction over rates, service, issuance of securities, safety, accounting and depreciation practices and other matters. In general, the FPSC sets rates at a level that allows utilities such as Tampa Electric and PGS to collect total revenues (revenue requirements) equal to their cost of providing service, plus a reasonable return on invested capital.
	NMGC is subject to regulation by the NMPRC. The NMPRC has jurisdiction over the regulatory matters related, directly and indirectly, to NMGC providing service to its customers, including, among other things, rates, accounting procedures, securities issuances, and standards of service. NMGC must follow certain accounting guidance that pertains specifically to entities that are subject to such regulation. Comparable to the FPSC, the NMPRC sets rates at a level that allows utilities such as NMGC to collect total revenues (revenue requirement) equal to their cost of providing service, plus a reasonable return on invested capital.
	2011 NMGC Base Rate Case
	In March 2011, NMGC filed an application with the NMPRC seeking authority to increase NMGC’s base rates by approximately $34.5 million on a normalized annual basis. In September 2011, the parties to the base rate proceeding entered into a settlement. The parties filed an unopposed stipulation reflecting the terms of that settlement with the NMPRC and the unopposed stipulation was approved by the NMPRC on Jan. 31, 2012, revising, among other things, base rates for all service provided on or after Feb. 1, 2012. The revised rates contained in the NMPRC-approved settlement increased NMGC’s base rate revenue by approximately $21.5 million on a normalized annual basis. The monthly residential customer access fee increased from $9.59 to $11.50, with the remaining rate increase reflected in changes to volumetric delivery charges. The parties stipulated that the NMPRC-approved revised rates would not increase again prior to July 31, 2013. Subsequently, as part of the May 2014 Settlement and subsequent NMPRC order approving the TECO Energy acquisition of NMGC, the rates will be frozen at the approved 2012 levels until the end of 2017 as reported in Note 16.

	NMGC’s PGAC
	Comparable to the PGS accounting for gas costs, NMGC’s cost of gas sold generally consists of (i) the amount paid to purchase the gas itself, (ii) variable pipeline transportation charges, (iii) fixed pipeline demand charges, (iv) storage charges, (v) commodity hedging costs and gains, and (vi) other related items. Virtually all of NMGC’s cost of gas sold is accounted for through an NMPRC-approved mechanism referred to as the PGAC. The PGAC is a ratemaking mechanism that allows for the adjustment of the gas commodity charge component of rates charged to gas sales service customers (referred to as the GCBF rate) to reflect monthly increases and decreases in NMGC’s cost of gas sold. Under this mechanism, gas sales service customers are charged a GCBF rate that allows NMGC to recoup its actual cost of gas sold to those customers on a near real-time basis. On a monthly basis, NMGC estimates its cost of gas for the next month (taking into consideration the expected cost of gas to be purchased for the next month, expected demand and any prior month under-recovery or over-recovery of NMGC’s cost of gas) and sets the GCBF rate to be used in the next month to recover those estimated costs. For any increase or decrease in cost of gas sold, there is a corresponding increase or decrease in revenue collected through the PGAC. NMGC’s cost of gas sold is charged to customers with no mark-up and, therefore, NMGC does not earn any gross margin on the gas commodity charge component of customer bills. Despite the fact that NMGC does not earn any gross margin on the gas commodity charge component of customer bills, this portion of customer bills may generate significant increases or decreases in NMGC’s revenues, due to changes in the market price of natural gas.
	At any point in time, NMGC typically will be in either an under-recovery or over-recovery position with respect to its cost of gas. An under-recovery or over-recovery occurs when there are differences between the cost of gas billed to customers through the PGAC and the actual cost of gas incurred by NMGC. The under-recovery or over-recovery is a cumulative continuous balance from month to month. An over-recovery of these costs is reflected in Regulatory Liabilities in the current liabilities section of the company’s Statements of Financial Position. An under-recovery of these costs is reflected in Regulatory Assets in the current assets section of the company’s Statements of Financial Position.
	NMGC also has regulatory authority to include a simple interest charge or credit, termed the PGAC Carrying Charge, in the PGAC and thus the GCBF rate, based upon the month-end balance of the PGAC under-recovery or over-recovery of NMGC’s cost of gas. PGAC Carrying Charges are reflected in Other Income in the company’s Statements of Operations.
	NMGC’s annual PGAC period runs from Sept. 1 to Aug. 31. NMGC’s objective is to complete each annual PGAC period with no significant under-recovery or over-recovery of its cost of gas. The NMPRC requires that NMGC file an independently-audited reconciliation of the PGAC period costs and recoveries, annually in December. Additionally, NMGC must file a PGAC Continuation Filing with the NMPRC every four years. The most recent PGAC Continuation Filing was submitted to the NMPRC in June 2012. The purpose of the PGAC Continuation Filing is to establish that the continued use of the PGAC is reasonable and necessary. In January 2013, the NMPRC approved the PGAC Continuation Filing, which essentially allows for the continued use of the PGAC for another four years.

	TEC Storm Damage Cost Recovery
	Prior to Nov. 1, 2013, Tampa Electric was accruing $8.0 million annually to a FERC-authorized and FPSC-approved self-insured storm damage reserve. This reserve was created after Florida’s IOUs were unable to obtain transmission and distribution insurance coverage due to destructive acts of nature. Effective Nov. 1, 2013, Tampa Electric ceased accruing for this storm damage reserve as a result of the 2013 rate case settlement. However, in the event of a named storm that results in damage to its system, Tampa Electric can petition the FPSC to seek recovery of those costs over a 12-month period or longer as determined by the FPSC, as well as replenish its reserve to $56.1 million; the level it was as of Oct. 31, 2013. Tampa Electric’s storm reserve remained $56.1 million at both Sept. 30, 2014 and Dec. 31, 2013.

	Regulatory Assets and Liabilities
	Tampa Electric and PGS maintain their accounts in accordance with recognized policies of the FPSC, while NMGC maintains its books in accordance with recognized policies of the NMPRC. In addition, Tampa Electric and NMGC maintain their accounts in accordance with recognized policies prescribed or permitted by the FERC.
	Tampa Electric, PGS and NMGC apply the accounting standards for regulated operations. Areas of applicability include: deferral of revenues under approved regulatory agreements; revenue recognition resulting from cost-recovery clauses that provide for monthly billing charges to reflect increases or decreases in fuel, purchased power, conservation and environmental costs; and the deferral of costs as regulatory assets to the period in which the regulatory agency recognizes them, when cost recovery is ordered over a period longer than a fiscal year.

	Details of the regulatory assets and liabilities as of Sept. 30, 2014 and Dec. 31, 2013 are presented in the following table:

	Regulatory Assets and Liabilities
	(millions)	30-Sep-14		31-Dec-13
	Regulatory assets:
	Regulatory tax asset (1)	$	69.1	$	67.4
	Other:
	Cost-recovery clauses		9.3		6.1
	Postretirement benefit asset (2)		194.1		182.7
	Deferred bond refinancing costs (3)		9.2		8
	Debt basis adjustment (3)		21.7		0
	Environmental remediation		52.3		51.4
	Competitive rate adjustment		2.6		4.1
	Other		8.2		7.7
	Total other regulatory assets		297.4		260
	Total regulatory assets		366.5		327.4
	Less: Current portion		24.3		34.3
	Long-term regulatory assets	$	342.2	$	293.1
	Regulatory liabilities:
	Regulatory tax liability (1)	$	6.7	$	9.8
	Other:
	Cost-recovery clauses		34.6		54.5
	Transmission and delivery storm reserve		56.1		56.1
	Deferred gain on property sales (4)		1.1		2
	Accumulated reserve - cost of removal		693.6		594
	Other		0.9		0.8
	Total other regulatory liabilities		786.3		707.4
	Total regulatory liabilities		793		717.2
	Less: Current portion		65.8		85.8
	Long-term regulatory liabilities	$	727.2	$	631.4
	-1	Primarily related to plant life and derivative positions.
	-2	Amortized over remaining service life of plan participants.
	-3	Amortized over the term of the related debt instruments.
	-4	Amortized over a 5-year period with various ending dates.
	All regulatory assets are recovered through the regulatory process. The following table further details the regulatory assets and the related recovery periods:

	Regulatory Assets
		Sep 30,		Dec 31,
	(millions)	2014		2013
	Clause recoverable (1)	$	11.9	$	10.2
	Components of rate base (2)		199.3		185.6
	Regulatory tax assets (3)		69.1		67.4
	Capital structure and other (3)		86.2		64.2
	Total	$	366.5	$	327.4
-1	To be recovered through cost-recovery mechanisms approved by the FPSC on a dollar-for-dollar basis in the next year.
-2	Primarily reflects allowed working capital, which is included in rate base and earns a rate of return as permitted by the FPSC.
-3	“Regulatory tax assets” and “Capital structure and other” regulatory assets have a recoverable period longer than a fiscal year and are recognized over the period authorized by the regulatory agency. Also included are unamortized loan costs, which are amortized over the life of the related debt instruments. See footnotes 1 and 2 in the prior table for additional information.
Tampa Electric Company [Member]	'
Regulatory	'
	3. Regulatory
	Tampa Electric’s and PGS’s retail businesses are regulated by the FPSC. Tampa Electric is also subject to regulation by the FERC under PUHCA 2005. However, pursuant to a waiver granted in accordance with the FERC’s regulations, TECO Energy is not subject to certain accounting, record-keeping and reporting requirements prescribed by the FERC’s regulations under PUHCA 2005. The operations of PGS are regulated by the FPSC separately from the operations of Tampa Electric. The FPSC has jurisdiction over rates, service, issuance of securities, safety, accounting and depreciation practices and other matters. In general, the FPSC sets rates at a level that allows utilities such as Tampa Electric and PGS to collect total revenues (revenue requirements) equal to their cost of providing service, plus a reasonable return on invested capital.
	Storm Damage Cost Recovery
	Prior to Nov. 1, 2013, Tampa Electric was accruing $8.0 million annually to a FERC-authorized and FPSC-approved self-insured storm damage reserve. This reserve was created after Florida’s IOUs were unable to obtain transmission and distribution insurance coverage due to destructive acts of nature. Effective Nov. 1, 2013, Tampa Electric ceased accruing for this storm damage reserve as a result of the 2013 rate case settlement. However, in the event of a named storm that results in damage to its system, Tampa Electric can petition the FPSC to seek recovery of those costs over a 12-month period or longer as determined by the FPSC, as well as replenish its reserve to $56.1 million; the level it was as of Oct. 31, 2013. Tampa Electric’s storm reserve remained $56.1 million at both Sept. 30, 2014 and Dec. 31, 2013.

	Regulatory Assets and Liabilities
	Tampa Electric and PGS maintain their accounts in accordance with recognized policies of the FPSC. In addition, Tampa Electric maintains its accounts in accordance with recognized policies prescribed or permitted by the FERC.
	Tampa Electric and PGS apply the accounting standards for regulated operations. Areas of applicability include: deferral of revenues under approved regulatory agreements; revenue recognition resulting from cost-recovery clauses that provide for monthly billing charges to reflect increases or decreases in fuel, purchased power, conservation and environmental costs; and the deferral of costs as regulatory assets to the period in which the regulatory agency recognizes them, when cost recovery is ordered over a period longer than a fiscal year.


	Details of the regulatory assets and liabilities as of Sept. 30, 2014 and Dec. 31, 2013 are presented in the following table:

	Regulatory Assets and Liabilities
	(millions)	30-Sep-14		31-Dec-13
	Regulatory assets:
	Regulatory tax asset (1)	$	68.6	$	67.4
	Other:
	Cost-recovery clauses		8		6.1
	Postretirement benefit asset (2)		187.8		182.7
	Deferred bond refinancing costs (3)		7.4		8
	Environmental remediation		52.3		51.4
	Competitive rate adjustment		2.6		4.1
	Other		7.9		7.7
	Total other regulatory assets		266		260
	Total regulatory assets		334.6		327.4
	Less: Current portion		22.9		34.3
	Long-term regulatory assets	$	311.7	$	293.1
	Regulatory liabilities:
	Regulatory tax liability (1)	$	5.3	$	9.8
	Other:
	Cost-recovery clauses		33.1		54.5
	Transmission and delivery storm reserve		56.1		56.1
	Deferred gain on property sales (4)		1.1		2
	Accumulated reserve - cost of removal		591.5		594
	Other		0.9		0.8
	Total other regulatory liabilities		682.7		707.4
	Total regulatory liabilities		688		717.2
	Less: Current portion		64.5		85.8
	Long-term regulatory liabilities	$	623.5	$	631.4
	-1	Primarily related to plant life and derivative positions.
	-2	Amortized over the remaining service life of plan participants.
	-3	Amortized over the term of the related debt instruments.
	-4	Amortized over a 5-year period with various ending dates.
	All regulatory assets are recovered through the regulatory process. The following table further details the regulatory assets and the related recovery periods:

	Regulatory Assets
		Sep 30,		Dec 31,
	(millions)	2014		2013
	Clause recoverable (1)	$	10.6	$	10.2
	Components of rate base (2)		190.9		185.6
	Regulatory tax assets (3)		68.6		67.4
	Capital structure and other (3)		64.5		64.2
	Total	$	334.6	$	327.4
	-1	To be recovered through cost-recovery mechanisms approved by the FPSC on a dollar-for-dollar basis in the next year.
	-2	Primarily reflects allowed working capital, which is included in rate base and earns a rate of return as permitted by the FPSC.
	-3	“Regulatory tax assets” and “Capital structure and other” regulatory assets have a recoverable period longer than a fiscal year and are recognized over the period authorized by the regulatory agency. Also included are unamortized loan costs, which are amortized over the life of the related debt instruments. See footnotes 1 and 2 in the prior table for additional information.

Income_Taxes

Income Taxes	9 Months Ended
Income Taxes	Sep. 30, 2014
Income Taxes	'
	4. Income Taxes
	The company’s U.S. subsidiaries join in the filing of a U.S. federal consolidated income tax return. The IRS concluded its examination of the company’s 2012 consolidated federal income tax return in January 2014. The U.S. federal statute of limitations remains open for years 2010 and forward. Years 2013 and 2014 are currently under examination by the IRS under its Compliance Assurance Program. TECO Energy does not expect the results of current IRS examinations to significantly change the total amount of unrecognized tax benefits by the end of 2014. U.S. state jurisdictions have statutes of limitations generally ranging from three to four years from the filing of an income tax return. The state impact of any federal changes remains subject to examination by various states for a period of up to one year after formal notification to the states. Years still open to examination by tax authorities in major state and foreign jurisdictions for continuing operations include 2010 and forward.
	The effective tax rate decreased to 35.38% for the nine months ended Sept. 30, 2014 from 37.35% for the same period in 2013. The decrease in the effective tax rate is the result of a state consolidated tax adjustment related to the acquisition of NMGC in the third quarter of 2014.
Tampa Electric Company [Member]	'
Income Taxes	'
	4. Income Taxes

	TEC is included in the filing of a consolidated federal income tax return with TECO Energy and its affiliates. TEC’s income tax expense is based upon a separate return computation. TEC’s effective tax rates for the nine months ended Sept. 30, 2014 and 2013 differ from the statutory rate principally due to state income taxes, the domestic activity production deduction and the AFUDC-equity.
	The IRS concluded its examination of TECO Energy’s 2012 consolidated federal income tax return in January 2014. The U.S. federal statute of limitations remains open for the year 2010 and forward. Years 2013 and 2014 are currently under examination by the IRS under its Compliance Assurance Program. TECO Energy does not expect the results of current IRS examinations to significantly change the total amount of unrecognized tax benefits by the end of 2014. Florida’s statute of limitations is three years from the filing of an income tax return. The state impact of any federal changes remains subject to examination by various states for a period of up to one year after formal notification to the states. Years still open to examination by Florida’s tax authorities include 2011 and forward.

Employee_Postretirement_Benefi

Employee Postretirement Benefits	9 Months Ended
Employee Postretirement Benefits	Sep. 30, 2014
Employee Postretirement Benefits	'
	5. Employee Postretirement Benefits
	Included in the table below is the periodic expense for pension and other postretirement benefits offered by the company.

	Pension Expense
	(millions)	Pension Benefits						Other Postretirement Benefits
	Three months ended Sep 30,	2014			2013			2014			2013
	Components of net periodic benefit expense
	Service cost	$	4.6		$	4.5		$	0.6		$	0.7
	Interest cost on projected benefit obligations		8			7.3			2.7			2.3
	Expected return on assets		(10.5	)		(9.6	)		(0.1	)		0
	Amortization of:
	Prior service (benefit) cost		(0.1	)		(0.1	)		0			(0.1	)
	Actuarial loss		3.3			5.1			0			0.2
	Regulatory asset		0			0			0.1			0
	Settlement cost		0			1			0			0
	Net pension expense recognized in the	$	5.3		$	8.2		$	3.3		$	3.1
	TECO Energy Consolidated Condensed Statements of Income	$	5.3		$	8.2		$	3.3		$	3.1
	Nine months ended Sep 30,
	Components of net periodic benefit expense
	Service cost	$	12.9		$	13.6		$	1.8		$	1.9
	Interest cost on projected benefit obligations		24.4			21.7			7.9			7
	Expected return on assets		(31.2	)		(28.8	)		(0.1	)		0
	Amortization of:
	Prior service (benefit) cost		(0.3	)		(0.3	)		(0.1	)		(0.3	)
	Actuarial loss		10			15.4			0.1			0.7
	Regulatory asset		0			0			0.1			0
	Settlement cost		0			1			0			0
	Net pension expense recognized in the	$	15.8		$	22.6		$	9.7		$	9.3
	TECO Energy Consolidated Condensed Statements of Income	$	15.8		$	22.6		$	9.7		$	9.3
	On Sept. 2, 2014, TECO Energy completed the purchase of NMGI, the holding company of NMGC. The employees of NMGC became participants of TECO Energy’s pension plan effective as of the closing date of the purchase; however, NMGC employees will remain in their current partially-funded other postretirement benefit plan. As such, remeasurements of TECO’s pension plan and NMGC’s other postretirement benefits plan were performed as of Sept. 2, 2014.
	For the remeasurement of the pension plan, TECO Energy is using an assumed long-term EROA of 7.00% and a discount rate of 4.277% for pension benefits under its qualified pension plan. TECO Energy assumed an EROA of 5.75% and a discount rate of 4.282% for the Sept. 2, 2014 measurement of NMGC’s other postretirement benefits. For the Jan. 1, 2014 measurement of TECO Energy’s other postretirement benefits, TECO Energy assumed a discount rate of 5.096%. Additionally, TECO Energy made contributions of $47.5 million to its pension plan for the nine months ended Sept. 30, 2014. Net pension expense presented above includes the effects of these items subsequent to Sept. 2, 2014.
	For the three and nine months ended Sept. 30, 2014, TECO Energy and its subsidiaries reclassed $0.7 million and $2.0 million pretax, respectively, of unamortized prior service benefit and actuarial losses from AOCI to net income as part of periodic benefit expense. In addition, during the three and nine months ended Sept. 30, 2014, the regulated companies reclassed $2.7 million and $7.9 million, respectively, of unamortized prior service benefit and actuarial losses from regulatory assets to net income as part of periodic benefit expense.

	Black Lung Liability
	TECO Coal is required by federal and state statutes to provide benefits to terminated, retired or (under state statutes) qualifying active employees for benefits related to black lung disease. TECO Coal is self-insured for black lung related claims. TECO Coal applies the accounting guidance of ACS 715 and annual expense is recorded for black lung obligations as determined by an independent actuary at the present value of the actuarially-computed liability for such benefits over the employee’s applicable term of service. At Sept. 30, 2014 and Dec. 31, 2013, TECO Coal had an actuarially-determined black lung liability of $27.8 million and $24.5 million, respectively. Expense related to the black lung liability recognized during the nine months ended Sept. 30, 2014 and 2013 was not material.
	As discussed in Notes 15 and 18, TECO Coal was classified as an asset held for sale at Sept. 30, 2014. In accordance with ACS 715, an after-tax settlement charge of approximately $7 million related to the unfunded black lung obligations recorded in accumulated other comprehensive income will be recognized as a loss from discontinued operations upon completion of the sale of TECO Coal which is expected to occur in the fourth quarter of 2014.
Tampa Electric Company [Member]	'
Employee Postretirement Benefits	'
	5. Employee Postretirement Benefits
	TEC is a participant in the comprehensive retirement plans of TECO Energy. Amounts allocable to all participants of the TECO Energy retirement plans are found in Note 5, Employee Postretirement Benefits, in the TECO Energy, Inc. Notes to Consolidated Condensed Financial Statements. TEC’s portion of the net pension expense for the three months ended Sept. 30, 2014 and 2013, respectively, was $3.6 million and $5.4 million for pension benefits, and $2.6 million and $2.5 million for other postretirement benefits. TEC’s portion of the net pension expense for the nine months ended Sept. 30, 2014 and 2013, respectively, was $11.3 million and $16.3 million for pension benefits, and $7.8 million and $7.5 million for other postretirement benefits.
	Due to the acquisition of NMGI on Sept. 2, 2014, TECO Energy’s pension plan was remeasured effective that date. For the remeasurement, TECO Energy assumed a long-term EROA of 7.00% and a discount rate of 4.277%. For the Jan. 1, 2014 measurement of TECO Energy’s other postretirement benefits, TECO Energy used a discount rate of 5.096%. Additionally, TECO Energy made contributions of $47.5 million to its pension plan in the nine months ended Sept. 30, 2014. TEC’s portion of the contributions was $38.2 million.
	Included in the benefit expenses discussed above, for the three and nine months ended Sept. 30, 2014, TEC reclassed $2.6 million and $7.8 million, respectively, of unamortized transition obligation, prior service cost and actuarial losses from regulatory assets to net income.

ShortTerm_Debt

Short-Term Debt	9 Months Ended
Short-Term Debt	Sep. 30, 2014
Short-Term Debt	'

	6. Short-Term Debt
	At Sept. 30, 2014 and Dec. 31, 2013, the following credit facilities and related borrowings existed:

	Credit Facilities
		30-Sep-14						31-Dec-13
						Letters						Letters
		Credit		Borrowings		of Credit		Credit		Borrowings		of Credit
	(millions)	Facilities		Outstanding (1)		Outstanding		Facilities		Outstanding (1)		Outstanding
	Tampa Electric Company:
	5-year facility (2)	$	325	$	0	$	0.7	$	325	$	6	$	0.7
	1-year accounts		150		0		0		150		78		0
	receivable facility		150		0		0		150		78		0
	TECO Energy/TECO Finance:
	5-year facility (2)(3)		300		55		0		200		0		0
	New Mexico Gas Company:
	5-year facility (2)		125		17		1.7		0		0		0
	Total	$	900	$	72	$	2.4	$	675	$	84	$	0.7

	(1) Borrowings outstanding are reported as notes payable.
	(2) This 5-year facility matures Dec. 17, 2018.
	(3) TECO Finance is the borrower and TECO Energy is the guarantor of this facility.

	At Sept. 30, 2014, these credit facilities required commitment fees ranging from 12.5 to 30.0 basis points. The weighted-average interest rate on outstanding amounts payable under the credit facilities at Sept. 30, 2014 and Dec. 31, 2013 was 1.37% and 0.56%, respectively.
	Tampa Electric Company Accounts Receivable Facility
	On Feb. 14, 2014, TEC and TRC amended their $150 million accounts receivable collateralized borrowing facility, entering into Amendment No. 12 to the Loan and Servicing Agreement with certain lenders named therein and Citibank, N.A. as Program Agent. The amendment (i) extends the maturity date to Feb. 13, 2015, (ii) provides that TRC will pay program and liquidity fees, which will total 70.0 basis points, (iii) continues to provide that the interest rates on the borrowings will be based on prevailing asset-backed commercial paper rates, unless such rates are not available from conduit lenders, in which case the rates will be at an interest rate equal to, at TEC’s option, either Citibank’s prime rate (or the federal funds rate plus 50 basis points, if higher) or a rate based on the LIBOR (if available) plus a margin, (iv) confirms that CAFCO, LLC will be the Committed Lender and Conduit Lender and (v) makes other technical changes.
	TECO Energy Credit Agreement Assigned to and Assumed by NMGC
	As previously disclosed, on Dec. 17, 2013, TECO Energy entered into a $125 million bank credit facility, pursuant to which it was the initial party to the Credit Agreement (the NMGC Credit Agreement). TECO Energy had no rights or obligations to borrow under the NMGC Credit Agreement, which was entered into solely with the intent of it being assigned to, and assumed by, NMGC upon the closing of the Acquisition. Pursuant to the terms of the NMGC Credit Agreement, on Sept. 2, 2014, TECO Energy designated NMGC as the borrower under the NMGC Credit Agreement by delivering a Joinder and Release Agreement duly executed by TECO Energy and NMGC, whereupon (i) NMGC became the borrower for all purposes of the NMGC Credit Agreement and the other credit facility documents under the NMGC Credit Agreement, and (ii) TECO Energy ceased to be a party to the NMGC Credit Agreement and any further rights or obligations thereunder. The NMGC Credit Agreement (i) has a maturity date of Dec. 17, 2018 (subject to further extension with the consent of each lender); (ii) allows NMGC to borrow funds at a rate equal to the one-month London interbank deposit rate plus a margin; (iii) as an alternative to the above interest rate, allows NMGC to borrow funds at an interest rate equal to a margin plus the higher of JPMorgan Chase Bank’s prime rate, the federal funds rate plus 50 basis points, or the London interbank deposit rate plus 1.00%; (iv) allows NMGC to borrow funds on a same-day basis under a Swingline Loan provision, which loans mature on the fourth Banking Day after which any such loans are made and bear interest at an interest rate as agreed by the Borrower and the relevant Swingline Lender prior to the making of any such loans; (v) allows NMGC to request the lenders to increase their commitments under the credit facility by up to $75 million in the aggregate; and (vi) includes a $40 million letter of credit facility.
	TECO Energy and TECO Finance Bridge Facility
	As previously disclosed, TECO Energy and TECO Finance entered into a $1.075 billion senior unsecured bridge credit agreement (the Bridge Facility) on Jun. 24, 2013, among TECO Energy as guarantor, TECO Finance as borrower, Morgan Stanley Senior Funding, Inc. (Morgan Stanley) as administrative agent, sole lead arranger and sole book runner, and Morgan Stanley together with nine other banks as lenders in the Bridge Facility. TECO Energy unconditionally guaranteed TECO Finance’s obligations under the Bridge Facility. In the third quarter of 2014, TECO Energy permanently financed the NMGC Acquisition with a combination of (i) a TECO Energy equity offering, (ii) the issuance of debt at NMGC and NMGI, (iii) cash on hand and (iv) short-term borrowings. Upon closing of the acquisition on Sept. 2, 2014, the commitment under the Bridge Facility was permanently cancelled by TECO Energy and TECO Finance.

	Amendment of TECO Energy/TECO Finance, Tampa Electric Company, and New Mexico Gas Company Bank Credit Facilities
	On Sept. 30, 2014, TECO Energy amended its $200 million bank credit facility, entering into Amendment No. 2 to its Fourth Amended and Restated Credit Agreement dated as of Dec. 17, 2013, as previously amended, (the TECO Credit Facility) whereby TECO Energy continues as Guarantor and its wholly-owned subsidiary, TECO Finance, continues as Borrower. The amendment increases the total commitments under the TECO Credit Facility to $300 million, changed the swingline commitments, and reallocates commitments among the lenders.
	On Sept. 30, 2014, TEC amended its $325 million bank credit facility, entering into Amendment No. 2 to its Fourth Amended and Restated Credit Agreement dated as of Dec. 17, 2013, as previously amended. The amendment changed the swingline commitments and reallocates commitments among the lenders.
	On Sept. 30, 2014, NMGC amended its $125 million bank credit facility, entering into Amendment No. 2 to its Credit Agreement dated as of Dec. 17, 2013, as previously amended. The amendment changed the swingline commitments and reallocates commitments among the lenders.

Tampa Electric Company [Member]	'
Short-Term Debt	'
	6. Short-Term Debt
	At Sept. 30, 2014 and Dec. 31, 2013, the following credit facilities and related borrowings existed:

	Credit Facilities
		30-Sep-14						31-Dec-13
						Letters						Letters
		Credit		Borrowings		of Credit		Credit		Borrowings		of Credit
	(millions)	Facilities		Outstanding (1)		Outstanding		Facilities		Outstanding (1)		Outstanding
	Tampa Electric Company:
	5-year facility (2)	$	325	$	0	$	0.7	$	325	$	6	$	0.7
	1-year accounts		150		0		0		150		78		0
	receivable facility		150		0		0		150		78		0
	Total	$	475	$	0	$	0.7	$	475	$	84	$	0.7
	-1	Borrowings outstanding are reported as notes payable.
	-2	This 5-year facility matures Dec. 17, 2018.
	At Sept. 30, 2014, these credit facilities required commitment fees ranging from 12.5 to 30.0 basis points. The weighted-average interest rate on outstanding amounts payable under the credit facilities at Dec. 31, 2013 was 0.56%. There were no outstanding borrowings at Sept. 30, 2014.

	Tampa Electric Company Accounts Receivable Facility
	On Feb. 14, 2014, TEC and TRC amended their $150 million accounts receivable collateralized borrowing facility, entering into Amendment No. 12 to the Loan and Servicing Agreement with certain lenders named therein and Citibank, N.A. as Program Agent. The amendment (i) extends the maturity date to Feb. 13, 2015, (ii) provides that TRC will pay program and liquidity fees, which will total 70.0 basis points, (iii) continues to provide that the interest rates on the borrowings will be based on prevailing asset-backed commercial paper rates, unless such rates are not available from conduit lenders, in which case the rates will be at an interest rate equal to, at TEC’s option, either Citibank’s prime rate (or the federal funds rate plus 50 basis points, if higher) or a rate based on the LIBOR (if available) plus a margin, (iv) confirms that CAFCO, LLC will be the Committed Lender and Conduit Lender and (v) makes other technical changes.
	On Sept. 30, 2014, TEC amended its $325 million bank credit facility, entering into Amendment No. 2 to its Fourth Amended and Restated Credit Agreement dated as of Dec. 17, 2013, as previously amended. The amendment modifies the swingline commitments and reallocates commitments among the lenders.

LongTerm_Debt

Long-Term Debt	9 Months Ended
Long-Term Debt	Sep. 30, 2014
Long-Term Debt	'
	7. Long-Term Debt
	Fair Value of Long-Term Debt
	At Sept. 30, 2014, total long-term debt had a carrying amount of $3,629.3 million and an estimated fair market value of $3,949.6 million. At Dec. 31, 2013, total long-term debt had a carrying amount of $2,921.1 million and an estimated fair market value of $3,184.1 million. The company uses the market approach in determining fair value. The majority of the outstanding debt is valued using real-time financial market data obtained from Bloomberg Professional Service. The remaining securities are valued using prices obtained from the Municipal Securities Rulemaking Board and by applying estimated credit spreads obtained from a third party to the par value of the security. All debt securities are Level 2 instruments.
	Issuance of Tampa Electric Company 4.35% Notes due 2044
	On May 15, 2014, TEC completed an offering of $300 million aggregate principal amount of 4.35% Notes due 2044 (the TEC 2014 Notes). The TEC 2014 Notes were sold at 99.933% of par. The offering resulted in net proceeds to TEC (after deducting underwriting discounts, commissions, estimated offering expenses and before settlement of interest rate swaps) of approximately $296.6 million. Net proceeds were used to repay short-term debt and for general corporate purposes. TEC may redeem all or any part of the TEC 2014 Notes at its option at any time and from time to time at a redemption price equal to the greater of (i) 100% of the principal amount of TEC 2014 Notes to be redeemed or (ii) the sum of the present value of the remaining payments of principal and interest on the notes to be redeemed, discounted at an applicable treasury rate (as defined in the indenture), plus 15 basis points; in either case, the redemption price would include accrued and unpaid interest to the redemption date. At any time on or after Nov. 15, 2043, TEC may at its option redeem the TEC 2014 Notes, in whole or in part, at 100% of the principal amount of the notes being redeemed plus accrued and unpaid interest thereon to but excluding the date of redemption.
	Issuance of New Mexico Gas Intermediate Series A Senior Unsecured 2.71% Notes due 2019
	On Sept. 2, 2014, NMGI completed an offering of $50 million aggregate principal amount of 2.71% Series A Senior Unsecured Notes due July 30, 2019 (the NMGI Series A Notes). The NMGI Series A Notes were sold at 100% of par. The offering resulted in net proceeds to NMGI (after deducting underwriting discounts, commissions and estimated offering expenses) of approximately $49.3 million. Net proceeds were used to repay existing indebtedness and for general corporate purposes. NMGI may redeem all or any part of the NMGI Series A Notes at its option at any time and from time to time at a redemption price equal to the greater of (i) 100% of the principal amount of NMGI Series A Notes to be redeemed or (ii) the sum of the present value of the remaining payments of principal and interest on the NMGI notes to be redeemed, discounted at an applicable reinvestment yield (as defined in the note purchase agreement), plus 50 basis points; in either case, the redemption price would include accrued and unpaid interest to the redemption date. The NMGI Series A Notes were issued in a private placement that was not subject to the registration requirements of the Securities Act of 1933.
	Issuance of New Mexico Gas Intermediate Series B Senior Unsecured 3.64 % Notes due 2024
	On Sept. 2, 2014, NMGI completed an offering of $150 million aggregate principal amount of 3.64% Series B Senior Unsecured Notes due July 30, 2024 (the NMGI Series B Notes). The NMGI Series B Notes were sold at 100% of par. The offering resulted in net proceeds to NMGI (after deducting underwriting discounts, commissions and estimated offering expenses) of approximately $149.1 million. Net proceeds were used to repay existing indebtedness and for general corporate purposes. NMGI may redeem all or any part of the NMGI Series B Notes at its option at any time and from time to time at a redemption price equal to the greater of (i) 100% of the principal amount of NMGI Series B Notes to be redeemed or (ii) the sum of the present value of the remaining payments of principal and interest on the NMGI notes to be redeemed, discounted at an applicable reinvestment yield (as defined in the note purchase agreement), plus 50 basis points; in either case, the redemption price would include accrued and unpaid interest to the redemption date. The NMGI Series B Notes were issued in a private placement that was not subject to the registration requirements of the Securities Act of 1933.
	Issuance of New Mexico Gas Company Senior Unsecured 3.54 % Notes due 2026
	On Sept. 2, 2014, NMGC completed an offering of $70 million aggregate principal amount of 3.54% Senior Unsecured Notes due July 30, 2026 (the NMGC 2014 Notes). The NMGC 2014 Notes were sold at 100% of par. The offering resulted in net proceeds to NMGC (after deducting underwriting discounts, commissions and estimated offering expenses) of approximately $69.3 million. Net proceeds were used to repay existing indebtedness and for general corporate purposes. NMGC may redeem all or any part of the NMGC 2014 Notes at its option at any time and from time to time at a redemption price equal to the greater of (i) 100% of the principal amount of NMGC 2014 Notes to be redeemed or (ii) the sum of the present value of the remaining payments of principal and interest on the notes to be redeemed, discounted at an applicable reinvestment yield (as defined in the note purchase agreement), plus 50 basis points; in either case, the redemption price would include accrued and unpaid interest to the redemption date. The NMGC 2014 Notes were issued in a private placement that was not subject to the registration requirements of the Securities Act of 1933.
	Amendment of New Mexico Gas Company 4.87 % Notes due 2021
	On Feb. 8, 2011, NMGC issued secured notes in an aggregate principal amount of $200 million (NMGC 2011 Notes), maturing Feb. 8, 2021. The NMGC 2011 Notes were issued in a private placement that was not subject to the registration requirements of the Securities Act of 1933.
	On July 16, 2014, NMGC received approvals from the noteholders of the NMGC 2011 Notes to release the collateral securing the NMGC 2011 Notes by amending the existing note purchase agreement. The amendments to the note purchase agreement were subject to the approval of the NMPRC and on Oct. 22, 2014, NMGC received the required NMPRC approval of the amendments. On Oct. 27, 2014, the amendments became effective and the collateral securing the NMGC 2014 Notes was released (see Note 18).
Tampa Electric Company [Member]	'
Long-Term Debt	'
	7. Long-Term Debt
	Fair Value of Long-Term Debt
	At Sept. 30, 2014, TEC’s total long-term debt had a carrying amount of $2,097.1 million and an estimated fair market value of $2,330.3 million. At Dec. 31, 2013, total long-term debt had a carrying amount of $1,880.8 million and an estimated fair market value of $2,042.0 million. TEC uses the market approach in determining fair value. The majority of the outstanding debt is valued using real-time financial market data obtained from Bloomberg Professional Service. The remaining securities are valued using prices obtained from the Municipal Securities Rulemaking Board and by applying estimated credit spreads obtained from a third party to the par value of the security. All debt securities are Level 2 instruments.
	Issuance of Tampa Electric Company 4.35% Notes due 2044
	On May 15, 2014, TEC completed an offering of $300 million aggregate principal amount of 4.35% Notes due 2044 (the TEC 2014 Notes). The TEC 2014 Notes were sold at 99.933% of par. The offering resulted in net proceeds to TEC (after deducting underwriting discounts, commissions, estimated offering expenses and before settlement of interest rate swaps) of approximately $296.6 million. Net proceeds were used to repay short-term debt and for general corporate purposes. TEC may redeem all or any part of the TEC 2014 Notes at its option at any time and from time to time at a redemption price equal to the greater of (i) 100% of the principal amount of TEC 2014 Notes to be redeemed or (ii) the sum of the present value of the remaining payments of principal and interest on the TEC 2014 Notes to be redeemed, discounted at an applicable treasury rate (as defined in the indenture), plus 15 basis points; in either case, the redemption price would include accrued and unpaid interest to the redemption date. At any time on or after Nov. 15, 2043, TEC may at its option redeem the TEC 2014 Notes, in whole or in part, at 100% of the principal amount of the TEC 2014 Notes being redeemed plus accrued and unpaid interest thereon to but excluding the date of redemption.

Other_Comprehensive_Income

Other Comprehensive Income	9 Months Ended
Other Comprehensive Income	Sep. 30, 2014
Other Comprehensive Income	'
	8. Other Comprehensive Income
	TECO Energy reported the following OCI for the three and nine months ended Sept. 30, 2014 and 2013, related to changes in the fair value of cash flow hedges and amortization of unrecognized benefit costs associated with the company’s postretirement plans:

	Other Comprehensive Income
		Three months ended Sep 30,									Nine months ended Sep 30,
	(millions)	Gross			Tax			Net			Gross			Tax			Net
	2014
	Unrealized loss on cash flow hedges	$	(0.3	)	$	0.1		$	(0.2	)	$	(0.3	)	$	0.1		$	(0.2	)
	Reclassification from AOCI to net income (1)		0.4			(0.1	)		0.3			0.9			(0.3	)		0.6
	Gain on cash flow hedges		0.1			0			0.1			0.6			(0.2	)		0.4
	Amortization of unrecognized benefit costs (2)		0.4			(0.2	)		0.2			2.4			(0.8	)		1.6
	Increase in unrecognized postemployment costs (3)		0			0			0			(12.9	)		4.7			(8.2	)
	Change in benefit obligation due to remeasurement		(1.1	)		0.4			(0.7	)		(1.1	)		0.4			(0.7	)
	Total other comprehensive income (loss) from continuing operations	$	(0.6	)	$	0.2		$	(0.4	)	$	(11.0	)	$	4.1		$	(6.9	)
	2013
	Unrealized gain on cash flow hedges	$	1.1		$	(0.4	)	$	0.7		$	0.7		$	(0.3	)	$	0.4
	Reclassification from AOCI to net income (1)		0.1			0			0.1			1			(0.3	)		0.7
	Gain on cash flow hedges		1.2			(0.4	)		0.8			1.7			(0.6	)		1.1
	Amortization of unrecognized benefit costs (2)		1			(0.4	)		0.6			3.2			(1.2	)		2
	Recognized benefit costs due to settlement		2.6			(1.0	)		1.6			2.6			(1.0	)		1.6
	Total other comprehensive income from continuing operations	$	4.8		$	(1.8	)	$	3		$	7.5		$	(2.8	)	$	4.7
	(1) Related to interest rate contracts recognized in Interest expense and commodity contracts recognized in Loss from discontinued operations.
	(2) Related to postretirement and postemployment benefits. See Note 5 for additional information.
	(3) Amounts reflect an out-of-period adjustment related to TECO Coal's unfunded black lung liability.



	Accumulated Other Comprehensive Loss
	(millions)	30-Sep-14			31-Dec-13
	Unrecognized pension loss and prior service credit (1)	$	(19.9	)	$	(20.5	)
	Unrecognized other benefit loss, prior service cost and		7.2			15.1
	transition obligation (2)		7.2			15.1
	Net unrealized losses from cash flow hedges (3)		(7.4	)		(7.8	)
	Total accumulated other comprehensive loss	$	(20.1	)	$	(13.2	)

	(1) Net of tax benefit of $12.3 million and $12.6 million as of Sept. 30, 2014 and Dec. 31, 2013, respectively.
	(2) Net of tax expense of $4.4 million and $9.1 million as of Sept. 30, 2014 and Dec. 31, 2013, respectively. Balance includes a $7.8 million loss related to TECO Coal's unfunded black lung liability that will be reclassified from AOCI to net income from discontinued operations upon the settlement of the black lung obligation at the sale date. See Note 18.
	(3) Net of tax benefit of $4.7 million and $4.9 million as of Sept. 30, 2014 and Dec. 31, 2013, respectively.


Tampa Electric Company [Member]	'
Other Comprehensive Income	'
	12. Other Comprehensive Income

	Other Comprehensive Income	Three months ended Sep 30,									Nine months ended Sep 30,
	(millions)	Gross			Tax			Net			Gross			Tax			Net
	2014
	Unrealized loss on cash flow hedges	$	0		$	0		$	0		$	0		$	0		$	0
	Reclassification from AOCI to net income		0.4			(0.1	)		0.3			0.8			(0.3	)		0.5
	Gain on cash flow hedges		0.4			(0.1	)		0.3			0.8			(0.3	)		0.5
	Total other comprehensive income	$	0.4		$	(0.1	)	$	0.3		$	0.8		$	(0.3	)	$	0.5
	2013
	Unrealized loss on cash flow hedges	$	0		$	0		$	0		$	0		$	0		$	0
	Reclassification from AOCI to net income		0.4			(0.2	)		0.2			1.1			(0.4	)		0.7
	Gain on cash flow hedges		0.4			(0.2	)		0.2			1.1			(0.4	)		0.7
	Total other comprehensive income	$	0.4		$	(0.2	)	$	0.2		$	1.1		$	(0.4	)	$	0.7



	Accumulated Other Comprehensive Loss
	(millions)	30-Sep-14			31-Dec-13
	Net unrealized losses from cash flow	$	(7.3	)	$	(7.8	)
	hedges (1)	$	(7.3	)	$	(7.8	)
	Total accumulated other	$	(7.3	)	$	(7.8	)
	comprehensive loss	$	(7.3	)	$	(7.8	)
	-1	Net of tax benefit of $4.6 million and $4.9 million as of Sept. 30, 2014 and Dec. 31, 2013, respectively.

Earnings_Per_Share

Earnings Per Share	9 Months Ended
Earnings Per Share	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Earnings Per Share	'
	9. Earnings Per Share

		For the three months ended Sep 30,						For the nine months ended Sep 30,
	(millions, except per share amounts)	2014			2013 (1)			2014			2013 (1)
	Basic earnings per share
	Net income from continuing operations	$	73		$	64.3		$	179		$	153.3
	Amount allocated to nonvested participating shareholders		(0.2	)		(0.2	)		(0.6	)		(0.5	)
	Income before discontinued operations available to	$	72.8		$	64.1		$	178.4		$	152.8
	common shareholders - Basic	$	72.8		$	64.1		$	178.4		$	152.8
	Income (Loss) from discontinued operations, net	$	(61.9	)	$	(1.5	)	$	(59.4	)	$	2.4
	Amount allocated to nonvested participating shareholders		0			0			0			0
	Income (Loss) from discontinued operations available to	$	(61.9	)	$	(1.5	)	$	(59.4	)	$	2.4
	common shareholders - Basic	$	(61.9	)	$	(1.5	)	$	(59.4	)	$	2.4
	Net income	$	11.1		$	62.8		$	119.6		$	155.7
	Amount allocated to nonvested participating shareholders		(0.2	)		(0.2	)		(0.6	)		(0.5	)
	Net income available to common shareholders - Basic	$	10.9		$	62.6		$	119		$	155.2
	Average common shares outstanding - Basic		227.8			215.2			220.3			214.9
	Earnings per share from continuing operations available to	$	0.32		$	0.3		$	0.81		$	0.71
	common shareholders - Basic	$	0.32		$	0.3		$	0.81		$	0.71
	Earnings per share from discontinued operations available to	$	(0.28	)	$	(0.01	)	$	(0.27	)	$	0.01
	common shareholders - Basic	$	(0.28	)	$	(0.01	)	$	(0.27	)	$	0.01
	Earnings per share available to common shareholders - Basic	$	0.04		$	0.29		$	0.54		$	0.72
	Diluted earnings per share
	Net income from continuing operations	$	73		$	64.3		$	179		$	153.3
	Amount allocated to nonvested participating shareholders		(0.2	)		(0.2	)		(0.6	)		(0.5	)
	Income before discontinued operations available to	$	72.8		$	64.1		$	178.4		$	152.8
	common shareholders - Diluted	$	72.8		$	64.1		$	178.4		$	152.8
	Income (Loss) from discontinued operations, net	$	(61.9	)	$	(1.5	)	$	(59.4	)	$	2.4
	Amount allocated to nonvested participating shareholders		0			0			0			0
	Income (Loss) from discontinued operations available to	$	(61.9	)	$	(1.5	)	$	(59.4	)	$	2.4
	common shareholders - Diluted	$	(61.9	)	$	(1.5	)	$	(59.4	)	$	2.4
	Net income	$	11.1		$	62.8		$	119.6		$	155.7
	Amount allocated to nonvested participating shareholders		(0.2	)		(0.2	)		(0.6	)		(0.5	)
	Net income available to common shareholders - Diluted	$	10.9		$	62.6		$	119		$	155.2
	Unadjusted average common shares outstanding - Diluted		227.8			215.2			220.3			214.9
	Assumed conversion of stock options, unvested restricted stock and		0.5			0.4			0.5			0.5
	contingent performance shares, net		0.5			0.4			0.5			0.5
	Average common shares outstanding - Diluted		228.3			215.6			220.8			215.4
	Earnings per share from continuing operations available to	$	0.32		$	0.3		$	0.81		$	0.71
	common shareholders - Diluted	$	0.32		$	0.3		$	0.81		$	0.71
	Earnings per share from discontinued operations available to	$	(0.28	)	$	(0.01	)	$	(0.27	)	$	0.01
	common shareholders - Diluted	$	(0.28	)	$	(0.01	)	$	(0.27	)	$	0.01
	Earnings per share available to common shareholders - Diluted	$	0.04		$	0.29		$	0.54		$	0.72
	Anti-dilutive shares		0			0			0			0

	(1) All prior periods presented reflect the classification of TECO Coal as discontinued operations (see Note 15).

Commitments_and_Contingencies

Commitments and Contingencies	9 Months Ended
Commitments and Contingencies	Sep. 30, 2014
Commitments and Contingencies	'
	10. Commitments and Contingencies
	Legal Contingencies
	From time to time, TECO Energy and its subsidiaries are involved in various legal, tax and regulatory proceedings before various courts, regulatory commissions and governmental agencies in the ordinary course of its business. Where appropriate, accruals are made in accordance with accounting standards for contingencies to provide for matters that are probable of resulting in an estimable loss. While the outcome of such proceedings is uncertain, management does not believe that their ultimate resolution will have a material adverse effect on the company’s results of operations, financial condition or cash flows.
	Peoples Gas Legal Proceedings
	In November 2010, heavy equipment operated at a road construction site being conducted by Posen Construction, Inc. struck a natural gas line causing a rupture and ignition of the gas and an outage in the natural gas service to Lee and Collier counties, Florida. The suit filed in November 2011 by the Posen Construction, Inc. employee operating the heavy equipment involved in the incident in Lee County Circuit Court against PGS, Posen Construction, Inc. and a PGS contractor involved in the project, seeking damages for his injuries, remains pending.
	The company believes the claim in the pending action described above in this item is without merit and intends to defend the matter vigorously. The company is unable at this time to estimate the possible loss or range of loss with respect to this matter.
	New Mexico Gas Company - February 2011 Gas Shortages, System Emergencies, Curtailments of Service, and Related Litigation
	In February 2011, NMGC experienced gas shortages due to weather-related interruptions of electric service, weather-related problems on the systems of various interstate pipelines and in gas fields that are the sources of gas supplied to NMGC, and high weather-driven usage. This gas supply disruption and high usage resulted in the declaration of system emergencies by NMGC causing involuntary curtailments of gas utility service to approximately 28,700 customers (residential and business).

	In March 2011, a customer purporting to represent a class consisting of all “32,000 [sic] customers” who had their gas utility service curtailed during the early-February system emergencies filed a putative class action lawsuit against NMGC. In March 2011, the Town of Bernalillo, New Mexico, purporting to represent a class consisting of all “New Mexico municipalities and governmental entities who have suffered damages as a result of the natural gas utility shut off” also filed a putative class action lawsuit against NMGC, four of its officers, and John and Jane Does at NMGC. In July 2011, the plaintiff in the Bernalillo class action filed an amended complaint to add an additional plaintiff purporting to represent a class of all “similarly situated New Mexico private businesses and enterprises.”
	The two purported class action suits (three purported classes) were consolidated. In September 2014, the court entered a final order dismissing the consolidated cases in their entirety with prejudice. A written order is pending. Plaintiffs have stated an intention to appeal. The period for appeal expires 30 days after the written order is signed, which is expected in October 2014.
	Two lawsuits representing 18 insurance carriers have filed subrogation lawsuits for monies paid to their insureds as a result of the curtailment of natural gas service in February 2011. These subrogation matters are pending and discovery is proceeding. NMGC anticipates filing motions to dismiss similar to those filed in the class actions.
	NMGC believes these claims in the pending actions described above in this item are without merit and intends to defend the matters vigorously. The company is unable at this time to estimate the possible loss or range of loss with respect to these claims.
	Davis v. Tampa Electric Company, et. al.
	Thirty six year old Scott Davis died from mesothelioma in March 2014. His estate and his family are suing Tampa Electric as a result.
	Mr. Davis allegedly suffered exposure to asbestos dust brought home by his father and grandfather, both of whom had been employed as insulators and worked at various job sites throughout the Tampa area. Plaintiff's case against Tampa Electric and nineteen other defendants alleges, among other things, negligence, strict liability, household exposure, loss of consortium, and wrongful death.
	The company believes the claim in the pending action described above in this item is without merit and intends to defend the matter vigorously. The company is unable at this time to estimate the possible loss or range of loss with respect to this matter.
	TECO Guatemala Holdings, LLC v. The Republic of Guatemala
	On Dec. 19, 2013, the ICSID Tribunal hearing the arbitration claim of TGH, a wholly owned subsidiary of TECO Energy, Inc., against the Republic of Guatemala (Guatemala) under the DR – CAFTA, issued an award in the case (the Award). The ICSID Tribunal unanimously found in favor of TGH and awarded damages to TGH of approximately U.S. $21.1 million, plus interest from Oct. 21, 2010 at a rate equal to the U.S. prime rate plus 2%. In addition, the Tribunal ruled that Guatemala must reimburse TGH for approximately U.S. $7.5 million of the costs that it incurred in pursuing the arbitration. Pursuant to ICSID’s rules and procedures, each party had 120 days after the date of the Award to file an application for its annulment.
	On April 18, 2014, Guatemala filed an application for annulment of the entire Award (or, alternatively, certain parts of the Award) pursuant to applicable ICSID rules. Guatemala also requested that the enforcement of the Award be stayed while the annulment proceeding is pending. Under the applicable rules, the enforcement of the Award is provisionally stayed until the ad hoc committee that will be deciding Guatemala’s application is constituted and makes a decision regarding whether the stay should continue through the rest of the annulment proceeding.
	Also on April 18, 2014, TGH separately filed an application for partial annulment of the Award on the basis of certain deficiencies in the Tribunal’s determination of the amount of TGH’s damages. If TGH’s application is successful, TGH will be able to seek additional damages from Guatemala in a new arbitration proceeding.
	While the duration of the annulment proceedings is uncertain, a hearing is scheduled in October 2015 and the proceedings as a whole are expected to take approximately two years to conclude, with a decision by the ad hoc committee in mid- to late-2016. Pending the outcome of annulment proceedings, 2014 results to date do not reflect any benefit of this decision.
	Superfund and Former Manufactured Gas Plant Sites
	TEC, through its Tampa Electric and Peoples Gas divisions, is a PRP for certain superfund sites and, through its Peoples Gas division, for certain former manufactured gas plant sites. While the joint and several liability associated with these sites presents the potential for significant response costs, as of Sept. 30, 2014, TEC has estimated its ultimate financial liability to be $33.3 million, primarily at PGS. This amount has been accrued and is primarily reflected in the long-term liability section under “Other” on the Consolidated Condensed Balance Sheets. The environmental remediation costs associated with these sites, which are expected to be paid over many years, are not expected to have a significant impact on customer prices.
	The estimated amounts represent only the portion of the cleanup costs attributable to TEC. The estimates to perform the work are based on TEC’s experience with similar work, adjusted for site-specific conditions and agreements with the respective governmental agencies. The estimates are made in current dollars, are not discounted and do not assume any insurance recoveries.
	In instances where other PRPs are involved, most of those PRPs are creditworthy and are likely to continue to be creditworthy for the duration of the remediation work. However, in those instances that they are not, TEC could be liable for more than TEC’s actual percentage of the remediation costs.
	Factors that could impact these estimates include the ability of other PRPs to pay their pro-rata portion of the cleanup costs, additional testing and investigation which could expand the scope of the cleanup activities, additional liability that might arise from the cleanup activities themselves or changes in laws or regulations that could require additional remediation. Under current regulations, these costs are recoverable through customer rates established in subsequent base rate proceedings.

	Guarantees and Letters of Credit
	A summary of the face amount or maximum theoretical obligation and the year of expiration under letters of credit and guarantees as of Sept. 30, 2014 is as follows:

	Guarantees - TECO Energy
	(millions)	Year of expiration						Maximum
						After (1)		Theoretical		Liabilities Recognized
	Guarantees for the Benefit of:	2014		2015-2018		2018		Obligation		at Sep 30, 2014 (2)
	TECO Coal
	Fuel purchase related	$	0	$	0.7	$	4	$	4.7	$	0
	Other subsidiaries
	Fuel purchase/energy management		0		0		92.9		92.9		0.1
	Total	$	0	$	0.7	$	96.9	$	97.6	$	0.1

	Letters of Credit - Tampa Electric Company
	(millions)					After (1)				Liabilities Recognized
	Letters of Credit for the Benefit of:	2014		2015-2018		2018		Total		at Sep 30, 2014 (2)
	Tampa Electric Company	$	0	$	0	$	0.7	$	0.7	$	0.1

	Letters of Credit - New Mexico Gas Company
	(millions)					After (1)				Liabilities Recognized
	Letters of Credit for the Benefit of:	2014		2015-2018		2018		Total		at Sep 30, 2014 (2)
	New Mexico Gas Company	$	0	$	0	$	1.7	$	1.7	$	1.3

	(1) These letters of credit and guarantees renew annually and are shown on the basis that they will continue to renew beyond 2018.
	(2) The amounts shown are the maximum theoretical amounts guaranteed under current agreements. Liabilities recognized represent the associated obligation of TECO Energy or TEC or NMGC under these agreements at Sept. 30, 2014. The obligations under these letters of credit and guarantees include net accounts payable and net derivative liabilities.


	Financial Covenants
	In order to utilize their respective bank facilities, TECO Energy and its subsidiaries must meet certain financial tests, including a debt to capital ratio, as defined in the applicable agreements. In addition, TECO Energy and its subsidiaries have certain restrictive covenants in specific agreements and debt instruments. At Sept. 30, 2014, TECO Energy and its subsidiaries were in compliance with all applicable financial covenants.
Tampa Electric Company [Member]	'
Commitments and Contingencies	'
	8. Commitments and Contingencies
	Legal Contingencies
	From time to time, TEC and its subsidiaries are involved in various legal, tax and regulatory proceedings before various courts, regulatory commissions and governmental agencies in the ordinary course of its business. Where appropriate, accruals are made in accordance with accounting standards for contingencies to provide for matters that are probable of resulting in an estimable loss. While the outcome of such proceedings is uncertain, management does not believe that their ultimate resolution will have a material adverse effect on the company’s results of operations, financial condition or cash flows.
	Peoples Gas Legal Proceedings
	In November 2010, heavy equipment operated at a road construction site being conducted by Posen Construction, Inc. struck a natural gas line causing a rupture and ignition of the gas and an outage in the natural gas service to Lee and Collier counties, Florida. The suit filed in November 2011 by the Posen Construction, Inc. employee operating the heavy equipment involved in the incident in Lee County Circuit Court against PGS, Posen Construction, Inc. and a PGS contractor involved in the project, seeking damages for his injuries, remains pending.
	TEC believes the claim in the pending action described above in this item is without merit and intends to defend the matter vigorously. TEC is unable at this time to estimate the possible loss or range of loss with respect to this matter.
	Davis v. Tampa Electric Company, et. al.
	Thirty six year old Scott Davis died from mesothelioma in March 2014. His estate and his family are suing Tampa Electric as a result.
	Mr. Davis allegedly suffered exposure to asbestos dust brought home by his father and grandfather, both of whom had been employed as insulators and worked at various job sites throughout the Tampa area. Plaintiff's case against Tampa Electric and nineteen other defendants alleges, among other things, negligence, strict liability, household exposure, loss of consortium, and wrongful death.
	TEC believes the claim in the pending action described above in this item is without merit and intends to defend the matter vigorously. The company is unable at this time to estimate the possible loss or range of loss with respect to this matter.
	Superfund and Former Manufactured Gas Plant Sites
	TEC, through its Tampa Electric and Peoples Gas divisions, is a PRP for certain superfund sites and, through its Peoples Gas division, for certain former manufactured gas plant sites. While the joint and several liability associated with these sites presents the potential for significant response costs, as of Sept. 30, 2014 TEC has estimated its ultimate financial liability to be $33.3 million, primarily at PGS. This amount has been accrued and is primarily reflected in the long-term liability section under “Other” on the Consolidated Condensed Balance Sheets. The environmental remediation costs associated with these sites, which are expected to be paid over many years, are not expected to have a significant impact on customer prices.
	The estimated amounts represent only the portion of the cleanup costs attributable to TEC. The estimates to perform the work are based on TEC’s experience with similar work, adjusted for site-specific conditions and agreements with the respective governmental agencies. The estimates are made in current dollars, are not discounted and do not assume any insurance recoveries.
	In instances where other PRPs are involved, most of those PRPs are creditworthy and are likely to continue to be creditworthy for the duration of the remediation work. However, in those instances that they are not, TEC could be liable for more than TEC’s actual percentage of the remediation costs.
	Factors that could impact these estimates include the ability of other PRPs to pay their pro-rata portion of the cleanup costs, additional testing and investigation which could expand the scope of the cleanup activities, additional liability that might arise from the cleanup activities themselves or changes in laws or regulations that could require additional remediation. Under current regulations, these costs are recoverable through customer rates established in subsequent base rate proceedings.
	Guarantees and Letters of Credit
	A summary of the face amount or maximum theoretical obligation under TEC’s letters of credit as of Sept. 30, 2014 is as follows:

	Letters of Credit - Tampa Electric Company
	(millions)					After (1)				Liabilities Recognized
	Letters of Credit for the Benefit of:	2014		2015-2018		2018		Total		at Sep 30, 2014
	Tampa Electric Company (2)	$	0	$	0	$	0.7	$	0.7	$	0.1
	-1	These letters of credit renew annually and are shown on the basis that they will continue to renew beyond 2018.
	-2	The amounts shown are the maximum theoretical amounts guaranteed under current agreements. Liabilities recognized represent the associated obligation of TEC under these agreements at Sept. 30, 2014. The obligations under these letters of credit include net accounts payable and net derivative liabilities.
	Financial Covenants
	In order to utilize its bank credit facilities, TEC must meet certain financial tests, including a debt to capital ratio, as defined in the applicable agreements. In addition, TEC has certain restrictive covenants in specific agreements and debt instruments. At Sept. 30, 2014, TEC was in compliance with all applicable financial covenants.

Segment_Information

Segment Information	9 Months Ended
Segment Information	Sep. 30, 2014
Segment Information	'
	11. Segment Information
	TECO Energy is an electric and gas utility holding company with diversified activities. Segments are determined based on how management evaluates, measures and makes decisions with respect to the operations of the entity. The management of TECO Energy reports segments based on each subsidiary’s contribution of revenues, net income and total assets as required by the accounting guidance for disclosures about segments of an enterprise and related information. All significant intercompany transactions are eliminated in the Consolidated Condensed Financial Statements of TECO Energy, but are included in determining reportable segments.


	Segment Information (1)
	(millions)	Tampa		Peoples		New Mexico			TECO			Other &			TECO
	Three months ended Sep 30,	Electric		Gas		Gas Co. (2)			Coal (1)			Eliminations (2)			Energy
	2014
	Revenues - external	$	581.5	$	86.9	$	16.2		$	0		$	2.6		$	687.2
	Sales to affiliates		0.3		0		0			0			(0.3	)		0
	Total revenues		581.8		86.9		16.2			0			2.3			687.2
	Depreciation and amortization		61.8		13.6		2.8			0			0.4			78.6
	Total interest charges		23.8		3.5		1.1			0			14.5			42.9
	Provision (benefit) for income taxes		48.5		3		(0.5	)		0			(17.3	)		33.7
	Net income (loss) from continuing operations		79.7		4.8		(0.9	)		0			(10.6	)		73
	Income from discontinued operations, net (1)		0		0		0			(64.8	)		2.9			(61.9	)
	Net income (loss)	$	79.7	$	4.8	$	(0.9	)	$	(64.8	)	$	(7.7	)	$	11.1
	2013
	Revenues - external	$	556.2	$	83.1	$	0		$	0		$	2.8		$	642.1
	Sales to affiliates		0.2		0.3		0			0			(0.5	)		0
	Total revenues		556.4		83.4		0			0			2.3			642.1
	Depreciation and amortization		62.2		13.4		0			0			0.5			76.1
	Total interest charges		22.8		3.4		0			0			13.7			39.9
	Provision (benefit) for income taxes		42.7		3.4		0			0			(7.2	)		38.9
	Net income (loss) from continuing operations		68.7		5.4		0			0			(9.8	)		64.3
	Income from discontinued operations, net (1)		0		0		0			(1.4	)		(0.1	)		(1.5	)
	Net income (loss)	$	68.7	$	5.4	$	0		$	(1.4	)	$	(9.9	)	$	62.8


	(millions)	Tampa		Peoples		New Mexico			TECO			Other &			TECO
	Nine months ended Sep 30,	Electric		Gas		Gas Co. (2)			Coal (1)			Eliminations (2)			Energy
	2014
	Revenues - external	$	1,546.90	$	300	$	16.2		$	0		$	7.8		$	1,870.90
	Sales to affiliates		0.8		0.6		0			0			(1.4	)		0
	Total revenues		1,547.70		300.6		16.2			0			6.4			1,870.90
	Depreciation and amortization		185.6		40.3		2.8			0			1.3			230
	Total interest charges		69.1		10.3		1.1			0			42.7			123.2
	Provision (benefit) for income taxes		112.2		17		(0.5	)		0			(30.7	)		98
	Net income (loss) from continuing operations		187.1		26.9		(0.9	)		0			(34.1	)		179
	Income from discontinued operations, net (1)		0		0		0			(65.6	)		6.2			(59.4	)
	Net income (loss)	$	187.1	$	26.9	$	(0.9	)	$	(65.6	)	$	(27.9	)	$	119.6
	2013
	Revenues - external	$	1,476.60	$	306.3	$	0		$	0		$	10		$	1,792.90
	Sales to affiliates		0.7		0.8		0			0			(1.5	)		0
	Total revenues		1,477.30		307.1		0			0			8.5			1,792.90
	Depreciation and amortization		182		39.6		0			0			1.2			222.8
	Total interest charges		69.5		10.1		0			0			42			121.6
	Provision (benefit) for income taxes		94		17.1		0			0			(19.7	)		91.4
	Net income (loss) from continuing operations		151.1		27.1		0			0			(24.9	)		153.3
	Income from discontinued operations, net (1)		0		0		0			2.3			0.1			2.4
	Net income (loss)	$	151.1	$	27.1	$	0		$	2.3		$	(24.8	)	$	155.7
	At Sep 30, 2014
	Goodwill	$	0	$	0	$	401.8		$	0		$	0		$	401.8
	Assets held for sale, current		0		0		0			133.7			0			133.7
	Assets held for sale, non-current		0		0		0			78.6			0			78.6
	Total assets	$	6,485.50	$	1,034.10	$	1,171.40		$	261.8		$	(299.2	)	$	8,653.60
	At Dec 31, 2013
	Total assets	$	6,126.90	$	1,021.20	$	0		$	316.3		$	(16.4	)	$	7,448.00

	(1) All periods have been adjusted to reflect the reclassification of results from operations to discontinued operations for TECO Coal and certain charges at Parent that directly relate to TECO Coal. See Note 15.
	(2) NMGI is included in the Other & Eliminations segment.


Tampa Electric Company [Member]	'
Segment Information	'
	9. Segment Information

	(millions)	Tampa		Peoples		Other &			Tampa Electric
	Three months ended Sep 30,	Electric		Gas		Eliminations			Company
	2014
	Revenues - external	$	581.6	$	86.9	$	0		$	668.5
	Sales to affiliates		0.2		0		(0.2	)		0
	Total revenues		581.8		86.9		(0.2	)		668.5
	Depreciation and amortization		61.8		13.6		0			75.4
	Total interest charges		23.8		3.5		0			27.3
	Provision for income taxes		48.5		3		0			51.5
	Net income	$	79.7	$	4.8	$	0		$	84.5
	2013
	Revenues - external	$	556.3	$	83.1	$	0		$	639.4
	Sales to affiliates		0.1		0.3		(0.4	)		0
	Total revenues		556.4		83.4		(0.4	)		639.4
	Depreciation and amortization		62.2		13.4		0			75.6
	Total interest charges		22.8		3.4		0			26.2
	Provision for income taxes		42.7		3.4		0			46.1
	Net income	$	68.7	$	5.4	$	0		$	74.1
	Nine months ended Sep 30,
	2014
	Revenues - external	$	1,547.30	$	300	$	0		$	1,847.30
	Sales to affiliates		0.4		0.6		(1.0	)		0
	Total revenues		1,547.70		300.6		(1.0	)		1,847.30
	Depreciation and amortization		185.6		40.3		0			225.9
	Total interest charges		69.1		10.3		0			79.4
	Provision for income taxes		112.2		17		0			129.2
	Net income	$	187.1	$	26.9	$	0		$	214
	Total assets at Sept. 30, 2014	$	6,160.80	$	1,002.40	$	(8.9	)	$	7,154.30
	2013
	Revenues - external	$	1,477.00	$	306.3	$	0		$	1,783.30
	Sales to affiliates		0.3		0.8		(1.1	)		0
	Total revenues		1,477.30		307.1		(1.1	)		1,783.30
	Depreciation and amortization		182		39.6		0			221.6
	Total interest charges		69.5		10.1		0			79.6
	Provision for income taxes		94		17.1		0			111.1
	Net income	$	151.1	$	27.1	$	0		$	178.2
	Total assets at Dec. 31, 2013	$	5,895.40	$	989.3	$	(8.9	)	$	6,875.80

Accounting_for_Derivative_Inst

Accounting for Derivative Instruments and Hedging Activities	9 Months Ended
	Sep. 30, 2014
Accounting for Derivative Instruments and Hedging Activities	'

	12. Accounting for Derivative Instruments and Hedging Activities
	From time to time, TECO Energy and its affiliates enter into futures, forwards, swaps and option contracts for the following purposes:
	—	to limit the exposure to price fluctuations for physical purchases and sales of natural gas in the course of normal operations at Tampa Electric, PGS and NMGC,
	—	to limit the exposure to interest rate fluctuations on debt securities at TECO Energy and its affiliates, and
	—	to limit the exposure to price fluctuations for physical purchases of fuel at TECO Coal.
	TECO Energy and its affiliates use derivatives only to reduce normal operating and market risks, not for speculative purposes. The company’s primary objective in using derivative instruments for regulated operations is to reduce the impact of market price volatility on ratepayers.
	The risk management policies adopted by TECO Energy provide a framework through which management monitors various risk exposures. Daily and periodic reporting of positions and other relevant metrics are performed by a centralized risk management group which is independent of all operating companies.
	The company applies the accounting standards for derivative instruments and hedging activities. These standards require companies to recognize derivatives as either assets or liabilities in the financial statements, to measure those instruments at fair value and to reflect the changes in the fair value of those instruments as either components of OCI or in net income, depending on the designation of those instruments. The changes in fair value that are recorded in OCI are not immediately recognized in current net income. As the underlying hedged transaction matures or the physical commodity is delivered, the deferred gain or loss on the related hedging instrument must be reclassified from OCI to earnings based on its value at the time of the instrument’s settlement. For effective hedge transactions, the amount reclassified from OCI to earnings is offset in net income by the market change of the amount paid or received on the underlying physical transaction.
	The company applies the accounting standards for regulated operations to financial instruments used to hedge the purchase of natural gas for its regulated companies. These standards, in accordance with the FPSC and NMPRC, permit the changes in fair value of natural gas derivatives to be recorded as regulatory assets or liabilities reflecting the impact of hedging activities on the fuel recovery clause. As a result, these changes are not recorded in OCI (see Note 3).
	A company’s physical contracts qualify for the NPNS exception to derivative accounting rules, provided they meet certain criteria. Generally, NPNS applies if the company deems the counterparty creditworthy, if the counterparty owns or controls resources within the proximity to allow for physical delivery of the commodity, if the company intends to receive physical delivery and if the transaction is reasonable in relation to the company’s business needs. As of Sept. 30, 2014, all of the company’s physical contracts qualify for the NPNS exception.
	The NMPRC allows, and generally expects, NMGC to have a commodity hedging program in order to hedge against increases in natural gas prices. Each year, NMGC develops an annual gas hedging plan, reviews that plan with the Staff of the NMPRC and representatives of the Attorney General of the State of New Mexico, and includes certain aspects of that plan in a report on NMGC’s annual gas supply plan which is filed with the NMPRC. As discussed in Note 3 under the caption NMGC’s PGAC, unless there are program-related disallowances, all costs associated with NMGC’s commodity hedging program are recoverable from customers through the PGAC, and any income or savings associated with the commodity hedging program are credited to customers through the PGAC. The instruments NMGC uses in its commodity hedging program are generally limited to fixed-price gas purchase contracts and call options. The fixed-price gas purchase contracts into which NMGC enters to serve its gas sales service customers qualify for the normal purchase and sales exception discussed previously and, therefore, those contracts are not recognized at fair value in the company’s Consolidated Condensed Balance Sheet.
	NMGC enters into numerous natural gas call option contracts for hedging purposes during the winter heating season. These call options allow NMGC to hedge specific quantities of natural gas at specified prices during the period from December through February. The premiums NMGC pays to enter into these call options are deferred at the time of payment in the company’s Consolidated Condensed Balance Sheet. These call option premiums are amortized in equal monthly amounts through the PGAC over the period from October through March. Cash received by NMGC from call options at expiration is credited to customers through the PGAC in the month in which the call options expire. Unamortized call option premiums are generally recorded as derivative assets, but when there are mark-to-market losses associated with these derivative assets, a portion, or all, of derivative assets are reclassified to regulatory assets in the company’s Consolidated Condensed Balance Sheet due to the recoverability of the unamortized call option premiums through the PGAC. The mark-to-market losses are limited to the amount of unamortized call option premiums at any point in time due to the regulatory treatment given to NMGC’s natural gas call options.

	The following table presents the derivatives that are designated as cash flow hedges at Sept. 30, 2014 and Dec. 31, 2013:

	Total Derivatives (1)
		Sep 30,				Dec 31,
	(millions)	2014				2013
	Current assets	$	0.2			$	9.7
	Long-term assets		0				0.3
	Total assets	$	0.2			$	10

	Current liabilities	$	4.1			$	0.1
	Long-term liabilities		1.6				0.2
	Total liabilities	$	5.7			$	0.3
	-1	Amounts presented above are on a gross basis, with asset and liability positions netted by counterparty in accordance with accounting standards for derivatives and hedging.
	The following table presents the gross amounts of derivatives and their related offset amounts as permitted by their respective master netting agreements at Sept. 30, 2014 and Dec. 31, 2013. There was no collateral posted with or received from any counterparties.

	Offsetting of Derivative Assets and Liabilities
	(millions)
		Gross Amounts of Recognized Assets (Liabilities)				Gross Amounts offset on the Balance Sheet				Net Amounts of Assets (Liabilities) Presented on the Balance Sheet
	30-Sep-14
	Description
	Derivative assets	$	1.4			$	(1.2	)		$	0.2
	Derivative liabilities	$	(6.9	)		$	1.2			$	(5.7	)

	31-Dec-13
	Description
	Derivative assets	$	10.5			$	(0.5	)		$	10
	Derivative liabilities	$	(0.8	)		$	0.5			$	(0.3	)
	The following table presents the derivative hedges of diesel fuel contracts at Sept. 30, 2014 and Dec. 31, 2013 to limit the exposure to changes in the market price for diesel fuel used in the production of coal. All diesel fuel derivatives are expected to be settled prior to the closing of the sale of TECO Coal.

	Diesel Fuel Derivatives
			Sep 30,				Dec 31,
	(millions)		2014				2013
	Current assets		$	0.1			$	0.2
	Long-term assets			0				0
	Total assets		$	0.1			$	0.2

	Current liabilities		$	0.1			$	0.1
	Long-term liabilities			0				0
	Total liabilities		$	0.1			$	0.1
	The following table presents the derivative hedges of natural gas contracts at Sept. 30, 2014 and Dec. 31, 2013 to limit the exposure to changes in market price for natural gas used to produce energy and natural gas purchased for resale to customers:

	Natural Gas Derivatives
			Sep 30,				Dec 31,
	(millions)		2014				2013
	Current assets		$	0.1			$	9.5
	Long-term assets			0				0.3
	Total assets		$	0.1			$	9.8

	Current liabilities		$	4			$	0
Long-term liabilities			1.6				0.2
Total liabilities		$	5.6			$	0.2
The ending balance in AOCI related to the cash flow hedges and interest rate swaps at Sept. 30, 2014 is a net loss of $7.4 million after tax and accumulated amortization. This compares to a net loss of $7.8 million in AOCI after tax and accumulated amortization at Dec. 31, 2013.
The following tables present the fair values and locations of derivative instruments recorded on the balance sheet at Sept. 30, 2014 and Dec. 31, 2013. All diesel fuel derivatives are expected to be settled prior to the closing on the sale of TECO Coal.


Derivatives Designated as Hedging Instruments
	Asset Derivatives						Liability Derivatives
(millions)	Balance Sheet		Fair				Balance Sheet		Fair
30-Sep-14	Location		Value				Location		Value
Commodity Contracts:

Diesel fuel derivatives:
Current	Derivative assets		$	0.1			Derivative liabilities		$	0.1
Long-term	Derivative assets			0			Derivative liabilities			0

Natural gas derivatives:
Current	Derivative assets			0.1			Derivative liabilities			4
Long-term	Derivative assets			0			Derivative liabilities			1.6
Total derivatives designated as hedging instruments			$	0.2					$	5.7

	Asset Derivatives						Liability Derivatives
(millions)	Balance Sheet		Fair				Balance Sheet		Fair
31-Dec-13	Location		Value				Location		Value
Commodity Contracts:

Diesel fuel derivatives:
Current	Derivative assets		$	0.2			Derivative liabilities		$	0.1
Long-term	Derivative assets			0			Derivative liabilities			0

Natural gas derivatives:
Current	Derivative assets			9.5			Derivative liabilities			0
Long-term	Derivative assets			0.3			Derivative liabilities			0.2
Total derivatives designated as hedging instruments			$	10					$	0.3
The following tables present the effect of energy related derivatives on the fuel recovery clause mechanism in the Consolidated Condensed Balance Sheets as of Sept. 30, 2014 and Dec. 31, 2013:

Energy Related Derivatives
	Asset Derivatives						Liability Derivatives
(millions)	Balance Sheet		Fair				Balance Sheet		Fair
30-Sep-14	Location (1)		Value				Location (1)		Value
Commodity Contracts:

Natural gas derivatives:
Current	Regulatory liabilities		$	0.1			Regulatory assets		$	4
Long-term	Regulatory liabilities			0			Regulatory assets			1.6
Total			$	0.1					$	5.6

(millions)	Balance Sheet		Fair				Balance Sheet		Fair
31-Dec-13	Location (1)		Value				Location (1)		Value
Commodity Contracts:

Natural gas derivatives:
Current	Regulatory liabilities		$	9.5			Regulatory assets		$	0
Long-term	Regulatory liabilities			0.3			Regulatory assets			0.2
Total			$	9.8					$	0.2
-1	Natural gas derivatives are deferred in accordance with accounting standards for regulated operations and all increases and decreases in the cost of natural gas supply are passed on to customers with the fuel recovery clause mechanism. As gains and losses are realized in future periods, they will be recorded as fuel costs in the Consolidated Condensed Statements of Income.
Based on the fair value of the instruments at Sept. 30, 2014, net pretax losses of $3.9 million are expected to be reclassified from regulatory assets or liabilities to the Consolidated Condensed Statements of Income within the next 12 months.
The following table presents the effect of hedging instruments on OCI and income for the three and nine months ended Sept. 30. All diesel fuel derivatives are expected to be settled prior to the closing on the sale of TECO Coal.

Effect of Hedging Instruments on OCI and Income
For the three months ended Sep 30:	Amount of				Location of		Amount of
	Gain/(Loss) on				Gain/(Loss)		Gain/(Loss)
	Derivatives				Reclassified		Reclassified
	Recognized in				From AOCI		From AOCI
(millions)	OCI				Into Income		Into Income
Derivatives in Cash Flow Hedging	Effective Portion (1)						Effective Portion (1)
Relationships	Effective Portion (1)						Effective Portion (1)
2014
Interest rate contracts	$	0			Interest expense		$	(0.3	)
Commodity contracts:
Diesel fuel derivatives		(0.2	)		Loss from discontinued operations			0
Total	$	(0.2	)				$	(0.3	)
2013
Interest rate contracts	$	0			Interest expense		$	(0.2	)
Commodity contracts:
Diesel fuel derivatives		0.7			Loss from discontinued operations			0.1
Total	$	0.7					$	(0.1	)



For the nine months ended Sep 30:	Amount of				Location of		Amount of
	Gain/(Loss) on				Gain/(Loss)		Gain/(Loss)
	Derivatives				Reclassified		Reclassified
	Recognized in				From AOCI		From AOCI
(millions)	OCI				Into Income		Into Income
Derivatives in Cash Flow Hedging	Effective Portion (1)						Effective Portion (1)
Relationships	Effective Portion (1)						Effective Portion (1)
2014
Interest rate contracts	$	0			Interest expense		$	(0.5	)
Commodity contracts:
Diesel fuel derivatives		(0.2	)		Loss from discontinued operations			(0.1	)
Total	$	(0.2	)				$	(0.6	)
2013
Interest rate contracts	$	0			Interest expense		$	(0.7	)
Commodity contracts:
Diesel fuel derivatives		0.4			Loss from discontinued operations			0
Total	$	0.4					$	(0.7	)
(1) Changes in OCI and AOCI are reported in after-tax dollars.
For derivative instruments that meet cash flow hedge criteria, the effective portion of the gain or loss on the derivative is reported as a component of OCI and reclassified into earnings in the same period or period during which the hedged transaction affects earnings. Gains and losses on the derivatives representing either hedge ineffectiveness or hedge components excluded from the assessment of effectiveness are recognized in current earnings. For the three and nine months ended Sept. 30, 2014 and 2013, all hedges were effective.
The following table presents the derivative activity for instruments classified as qualifying cash flow hedges for the nine months ended Sept. 30. All diesel fuel derivatives are expected to be settled prior to the closing on the sale of TECO Coal.

Qualifying Cash Flow Hedges
					Amount of				Amount of
	Fair Value				Gain/(Loss)				Gain/(Loss)
	Asset/				Recognized				Reclassified From
(millions)	(Liability)				in OCI (1)				AOCI Into Income
2014
Interest rate swaps	$	0			$	0			$	(0.5	)
Diesel fuel derivatives		0				(0.2	)			(0.1	)
Total	$	0			$	(0.2	)		$	(0.6	)
2013
Interest rate swaps	$	0			$	0			$	(0.7	)
Diesel fuel derivatives		0.1				0.4				0
Total	$	0.1			$	0.4			$	(0.7	)
-1	Changes in OCI and AOCI are reported in after-tax dollars.
The maximum length of time over which the company is hedging its exposure to the variability in future cash flows extends to Dec. 31, 2014 for financial diesel fuel contracts and Dec. 31, 2016 for financial natural gas contracts. The following table presents by commodity type the company’s derivative volumes that, as of Sept. 30, 2014, are expected to settle during the 2014, 2015 and 2016 fiscal years:

Derivative Volumes	Diesel Fuel Contracts								Natural Gas Contracts
(millions)	(Gallons)								(MMBTUs)
Year	Physical				Financial				Physical				Financial
2014		0				0.5				0				11.6
2015		0				0				0				32.2
2016		0				0				0				7.6
Total		0				0.5				0				51.4
The company is exposed to credit risk primarily through entering into derivative instruments with counterparties to limit its exposure to the commodity price fluctuations associated with diesel fuel and natural gas. Credit risk is the potential loss resulting from a counterparty’s nonperformance under an agreement. The company manages credit risk with policies and procedures for, among other things, counterparty analysis, exposure measurement and exposure monitoring and mitigation.
It is possible that volatility in commodity prices could cause the company to have material credit risk exposures with one or more counterparties. If such counterparties fail to perform their obligations under one or more agreements, the company could suffer a material financial loss. However, as of Sept. 30, 2014, substantially all of the counterparties with transaction amounts outstanding in the company’s energy portfolio were rated investment grade by the major rating agencies. The company assesses credit risk internally for counterparties that are not rated.
The company has entered into commodity master arrangements with its counterparties to mitigate credit exposure to those counterparties. The company generally enters into the following master arrangements: (1) EEI agreements - standardized power sales contracts in the electric industry; (2) ISDA agreements - standardized financial gas and electric contracts; and (3) NAESB agreements - standardized physical gas contracts. The company believes that entering into such agreements reduces the risk from default by creating contractual rights relating to creditworthiness, collateral and termination.
The company has implemented procedures to monitor the creditworthiness of its counterparties and to consider nonperformance risk in determining the fair value of counterparty positions. Net liability positions are generally not adjusted as the company uses derivative transactions as hedges and has the ability and intent to perform under each of these contracts. In the instance of net asset positions, the company considers general market conditions and the observable financial health and outlook of specific counterparties in evaluating the potential impact of nonperformance risk to derivative positions. As of Sept. 30, 2014, substantially all positions with counterparties were net liabilities.
Certain TECO Energy derivative instruments contain provisions that require the company’s debt, or in the case of derivative instruments where TEC is the counterparty, TEC’s debt, to maintain an investment grade credit rating from any or all of the major credit rating agencies. If debt ratings, including TEC’s, were to fall below investment grade, it could trigger these provisions, and the counterparties to the derivative instruments could request immediate payment or demand immediate and ongoing full overnight collateralization on derivative instruments in net liability positions. The company has no other contingent risk features associated with any derivative instruments. Substantially all of the company’s open positions with counterparties as of Sept. 30, 2014 were liability positions.
Tampa Electric Company [Member]	'
Accounting for Derivative Instruments and Hedging Activities	'
	10. Accounting for Derivative Instruments and Hedging Activities
	From time to time, TEC enters into futures, forwards, swaps and option contracts for the following purposes:
	—	to limit the exposure to price fluctuations for physical purchases and sales of natural gas in the course of normal operations, and
	—	to limit the exposure to interest rate fluctuations on debt securities.
	TEC uses derivatives only to reduce normal operating and market risks, not for speculative purposes. TEC’s primary objective in using derivative instruments for regulated operations is to reduce the impact of market price volatility on ratepayers.
	The risk management policies adopted by TEC provide a framework through which management monitors various risk exposures. Daily and periodic reporting of positions and other relevant metrics are performed by a centralized risk management group which is independent of all operating companies.
	TEC applies the accounting standards for derivatives and hedging. These standards require companies to recognize derivatives as either assets or liabilities in the financial statements, to measure those instruments at fair value and to reflect the changes in the fair value of those instruments as either components of OCI or in net income, depending on the designation of those instruments. The changes in fair value that are recorded in OCI are not immediately recognized in current net income. As the underlying hedged transaction matures or the physical commodity is delivered, the deferred gain or loss on the related hedging instrument must be reclassified from OCI to earnings based on its value at the time of the instrument’s settlement. For effective hedge transactions, the amount reclassified from OCI to earnings is offset in net income by the market change of the amount paid or received on the underlying physical transaction.
	TEC applies accounting standards for regulated operations to financial instruments used to hedge the purchase of natural gas for the regulated companies. These standards, in accordance with the FPSC, permit the changes in fair value of natural gas derivatives to be recorded as regulatory assets or liabilities reflecting the impact of hedging activities on the fuel recovery clause. As a result, these changes are not recorded in OCI (see Note 3).
	A company’s physical contracts qualify for the NPNS exception to derivative accounting rules, provided they meet certain criteria. Generally, NPNS applies if the company deems the counterparty creditworthy, if the counterparty owns or controls resources within the proximity to allow for physical delivery of the commodity, if the company intends to receive physical delivery and if the transaction is reasonable in relation to the company’s business needs. As of Sept. 30, 2014, all of TEC’s physical contracts qualify for the NPNS exception.
	The following table presents the derivative hedges of natural gas contracts at Sept. 30, 2014 and Dec. 31, 2013 to limit the exposure to changes in the market price for natural gas used to produce energy and natural gas purchased for resale to customers:

	Natural Gas Derivatives
		Sept. 30,				Dec. 31,
	(millions)	2014				2013
	Current assets	$	0.1			$	9.5
	Long-term assets		0				0.3
	Total assets	$	0.1			$	9.8
	Current liabilities (1)	$	4			$	0
	Long-term liabilities		1.6				0.2
	Total liabilities	$	5.6			$	0.2
	-1	Amounts presented above are on a gross basis, with asset and liability positions netted by counterparty in accordance with accounting standards for derivatives and hedging.
	The ending balance in AOCI related to previously settled interest rate swaps at Sept. 30, 2014 is a net loss of $7.3 million after tax and accumulated amortization. This compares to a net loss of $7.8 million in AOCI after tax and accumulated amortization at Dec. 31, 2013.
	The following table presents the gross amounts of derivatives and their related offset amounts as permitted by their respective master netting agreements at Sept. 30, 2014 and Dec. 31, 2013. There was no collateral posted with or received from any counterparties:

	Offsetting of Derivative Assets and Liabilities

	(millions)	Gross Amounts of Recognized Assets (Liabilities)				Gross Amounts offset on the Balance Sheet				Net Amounts of Assets (Liabilities) Presented on the Balance Sheet
	30-Sep-14
	Description
	Derivative assets	$	1.4			$	(1.3	)		$	0.1
	Derivative liabilities	$	(6.9	)		$	1.3			$	(5.6	)

	31-Dec-13
	Description
	Derivative assets	$	10.3			$	(0.5	)		$	9.8
	Derivative liabilities	$	(0.7	)		$	0.5			$	(0.2	)
	The following table presents the effect of energy related derivatives on the fuel recovery clause mechanism in the Consolidated Condensed Balance Sheets as of Sept. 30, 2014 and Dec. 31, 2013:

	Energy Related Derivatives
		Asset Derivatives						Liability Derivatives
	(millions)	Balance Sheet		Fair				Balance Sheet		Fair
	30-Sep-14	Location (1)		Value				Location (1)		Value
	Commodity Contracts:

	Natural gas derivatives:
	Current	Regulatory liabilities		$	0.1			Regulatory assets		$	4
	Long-term	Regulatory liabilities			0			Regulatory assets			1.6
	Total			$	0.1					$	5.6

	(millions)	Balance Sheet		Fair				Balance Sheet		Fair
	31-Dec-13	Location (1)		Value				Location (1)		Value
	Commodity Contracts:

	Natural gas derivatives:
	Current	Regulatory liabilities		$	9.5			Regulatory assets		$	0
	Long-term	Regulatory liabilities			0.3			Regulatory assets			0.2
	Total			$	9.8					$	0.2
	-1	Natural gas derivatives are deferred in accordance with accounting standards for regulated operations and all increases and decreases in the cost of natural gas supply are passed on to customers with the fuel recovery clause mechanism. As gains and losses are realized in future periods, they will be recorded as fuel costs in the Consolidated Condensed Statements of Income.
	Based on the fair value of the instruments at Sept. 30, 2014, net pretax losses of $3.9 million are expected to be reclassified from regulatory assets or liabilities to the Consolidated Condensed Statements of Income within the next 12 months.


	The following table presents the effect of hedging instruments on OCI and income for the three months and nine months ended Sept. 30:

(millions)	Location of Gain/(Loss) Reclassified From AOCI Into Income		Amount of Gain/(Loss) Reclassified From AOCI Into Income
Derivatives in Cash Flow Hedging Relationships	Effective Portion (1)		Three months				Nine months
Derivatives in Cash Flow Hedging Relationships	Effective Portion (1)		ended Sep 30:				ended Sep 30:
2014
Interest rate contracts:	Interest expense		$	(0.3	)		$	(0.5	)
Total			$	(0.3	)		$	(0.5	)
2013
Interest rate contracts:	Interest expense		$	(0.2	)		$	(0.7	)
Total			$	(0.2	)		$	(0.7	)
-1	Changes in OCI and AOCI are reported in after-tax dollars.
For derivative instruments that meet cash flow hedge criteria, the effective portion of the gain or loss on the derivative is reported as a component of OCI and reclassified into earnings in the same period or period during which the hedged transaction affects earnings. Gains and losses on the derivatives representing either hedge ineffectiveness or hedge components excluded from the assessment of effectiveness are recognized in current earnings. For the three and nine months ended Sept. 30, 2014 and 2013, all hedges were effective.
The maximum length of time over which TEC is hedging its exposure to the variability in future cash flows extends to Dec. 31, 2016 for the financial natural gas contracts. The following table presents by commodity type TEC’s derivative volumes that, as of Sept. 30, 2014, are expected to settle during the 2014, 2015 and 2016 fiscal years:

	Natural Gas Contracts
(millions)	(MMBTUs)
Year	Physical				Financial
2014		0				11.6
2015		0				32.2
2016		0				7.6
Total		0				51.4
TEC is exposed to credit risk primarily through entering into derivative instruments with counterparties to limit its exposure to the commodity price fluctuations associated with natural gas. Credit risk is the potential loss resulting from a counterparty’s nonperformance under an agreement. TEC manages credit risk with policies and procedures for, among other things, counterparty analysis, exposure measurement and exposure monitoring and mitigation.
It is possible that volatility in commodity prices could cause TEC to have material credit risk exposures with one or more counterparties. If such counterparties fail to perform their obligations under one or more agreements, TEC could suffer a material financial loss. However, as of Sept. 30, 2014, substantially all of the counterparties with transaction amounts outstanding in TEC’s energy portfolio were rated investment grade by the major rating agencies. TEC assesses credit risk internally for counterparties that are not rated.
TEC has entered into commodity master arrangements with its counterparties to mitigate credit exposure to those counterparties. TEC generally enters into the following master arrangements: (1) EEI agreements- standardized power sales contracts in the electric industry; (2) ISDA agreements- standardized financial gas and electric contracts; and (3) NAESB agreements - standardized physical gas contracts. TEC believes that entering into such agreements reduces the risk from default by creating contractual rights relating to creditworthiness, collateral and termination.
TEC has implemented procedures to monitor the creditworthiness of its counterparties and to consider nonperformance risk in determining the fair value of counterparty positions. Net liability positions are generally not adjusted as TEC uses derivative transactions as hedges and has the ability and intent to perform under each of these contracts. In the instance of net asset positions, TEC considers general market conditions and the observable financial health and outlook of specific counterparties in evaluating the potential impact of nonperformance risk to derivative positions. As of Sept. 30, 2014, substantially all positions with counterparties were net liabilities.
Certain TEC derivative instruments contain provisions that require TEC’s debt to maintain an investment grade credit rating from any or all of the major credit rating agencies. If debt ratings were to fall below investment grade, it could trigger these provisions, and the counterparties to the derivative instruments could request immediate payment or demand immediate and ongoing full overnight collateralization on derivative instruments in net liability positions. TEC has no other contingent risk features associated with any derivative instruments. Substantially all of TEC’s open positions with counterparties as of Sept. 30, 2014 were liability positions.

Fair_Value_Measurements

Fair Value Measurements	9 Months Ended
Fair Value Measurements	Sep. 30, 2014
Fair Value Measurements	'
	13. Fair Value Measurements
	Items Measured at Fair Value on a Recurring Basis

	Accounting guidance governing fair value measurements and disclosures provides that fair value represents the amount that would be received in selling an asset or the amount that would be paid in transferring a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that is determined based upon assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, accounting guidance also establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows:

	Level 1: Observable inputs, such as quoted prices in active markets;
	Level 2: Inputs, other than quoted prices in active markets, that are observable either directly or indirectly; and
	Level 3: Unobservable inputs for which there is little or no market data, which require the reporting entity to develop its own assumptions.

	Assets and liabilities are measured at fair value based on one or more of the following three valuation techniques noted under accounting guidance:

	(A) Market approach: Prices and other relevant information generated by market transactions involving
	identical or comparable assets or liabilities;
	(B) Cost approach: Amount that would be required to replace the service capacity of an asset (replacement
	cost); and
	(C) Income approach: Techniques to convert future amounts to a single present amount based upon market
	expectations (including present value techniques, option-pricing and excess earnings models).

	The fair value of financial instruments is determined by using various market data and other valuation techniques. At Sept. 30, 2014 and Dec. 31, 2013, the company did not have any financial assets or liabilities for which disclosures about fair value are required.
	The following tables set forth by level within the fair value hierarchy, the company’s financial assets and liabilities that were accounted for at fair value on a recurring basis as of Sept. 30, 2014 and Dec. 31, 2013. As required by accounting standards for fair value measurements, financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. The company’s assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the valuation of fair value assets and liabilities and their placement within the fair value hierarchy levels. For natural gas and diesel fuel swaps, the market approach was used in determining fair value.

	Recurring Fair Value Measures
		At fair value as of Sep 30, 2014
	(millions)	Level 1		Level 2		Level 3		Total
	Assets
	Natural gas swaps	$	0	$	0.1	$	0	$	0.1
	Diesel fuel swaps		0		0.1		0		0.1
	Total	$	0	$	0.2	$	0	$	0.2

	Liabilities
	Natural gas swaps	$	0	$	5.6	$	0	$	5.6
	Diesel fuel swaps		0		0.1		0		0.1
	Total	$	0	$	5.7	$	0	$	5.7


		At fair value as of Dec 31, 2013
	(millions)	Level 1		Level 2		Level 3		Total
	Assets
	Natural gas swaps	$	0	$	9.8	$	0	$	9.8
	Diesel fuel swaps		0		0.2		0		0.2
	Total	$	0	$	10	$	0	$	10

	Liabilities
	Natural gas swaps	$	0	$	0.2	$	0	$	0.2
	Diesel fuel swaps		0		0.1		0		0.1
	Total	$	0	$	0.3	$	0	$	0.3

	Natural gas and diesel fuel swaps are OTC swap instruments. The primary pricing inputs in determining the fair value of these swaps are the NYMEX quoted closing prices of exchange-traded instruments. These prices are applied to the notional amounts of active positions to determine the reported fair value (see Note 12).
	The company considered the impact of nonperformance risk in determining the fair value of derivatives. The company considered the net position with each counterparty, past performance of both parties, the intent of the parties, indications of credit deterioration and whether the markets in which the company transacts have experienced dislocation. At Sept. 30, 2014, the fair value of derivatives was not materially affected by nonperformance risk. There were no Level 3 assets or liabilities for the periods presented.
Tampa Electric Company [Member]	'
Fair Value Measurements	'
	11. Fair Value Measurements
	Items Measured at Fair Value on a Recurring Basis

	Accounting guidance governing fair value measurements and disclosures provides that fair value represents the amount that would be received in selling an asset or the amount that would be paid in transferring a liability in an orderly transaction between market participants. As such, fair value is a market-based measurement that is determined based upon assumptions that market participants would use in pricing an asset or liability. As a basis for considering such assumptions, accounting guidance also establishes a three-tier fair value hierarchy, which prioritizes the inputs used in measuring fair value as follows:

	Level 1: Observable inputs, such as quoted prices in active markets;
	Level 2: Inputs, other than quoted prices in active markets, that are observable either directly or indirectly; and
	Level 3: Unobservable inputs for which there is little or no market data, which require the reporting entity to develop its own assumptions.

	Assets and liabilities are measured at fair value based on one or more of the following three valuation techniques noted under accounting guidance:

	(A) Market approach: Prices and other relevant information generated by market transactions involving
	identical or comparable assets or liabilities;
	(B) Cost approach: Amount that would be required to replace the service capacity of an asset (replacement
	cost); and
	(C) Income approach: Techniques to convert future amounts to a single present amount based upon market
	expectations (including present value techniques, option-pricing and excess earnings models).

	The fair value of financial instruments is determined by using various market data and other valuation techniques. At Sept. 30, 2014 and Dec. 31, 2013, the company did not have any financial assets or liabilities for which disclosures about fair value are required.
	The following tables set forth by level within the fair value hierarchy, TEC’s financial assets and liabilities that were accounted for at fair value on a recurring basis as of Sept. 30, 2014 and Dec. 31, 2013. As required by accounting standards for fair value measurements, financial assets and liabilities are classified in their entirety based on the lowest level of input that is significant to the fair value measurement. TEC’s assessment of the significance of a particular input to the fair value measurement requires judgment, and may affect the valuation of fair value assets and liabilities and their placement within the fair value hierarchy levels. For all assets and liabilities presented below, the market approach was used in determining fair value.


	Recurring Derivative Fair Value Measures
		At fair value as of Sep 30, 2014
	(millions)	Level 1		Level 2		Level 3		Total
	Assets
	Natural gas swaps	$	0	$	0.1	$	0	$	0.1
	Total	$	0	$	0.1	$	0	$	0.1

	Liabilities
	Natural gas swaps	$	0	$	5.6	$	0	$	5.6
	Total	$	0	$	5.6	$	0	$	5.6

		At fair value as of Dec 31, 2013
	(millions)	Level 1		Level 2		Level 3		Total
	Assets
	Natural gas swaps	$	0	$	9.8	$	0	$	9.8
	Total	$	0	$	9.8	$	0	$	9.8

	Liabilities
	Natural gas swaps	$	0	$	0.2	$	0	$	0.2
	Total	$	0	$	0.2	$	0	$	0.2
	Natural gas swaps are OTC swap instruments. The primary pricing inputs in determining the fair value of natural gas swaps are the NYMEX quoted closing prices of exchange-traded instruments. These prices are applied to the notional amounts of active positions to determine the reported fair value (see Note 10).
	TEC considered the impact of nonperformance risk in determining the fair value of derivatives. TEC considered the net position with each counterparty, past performance of both parties, the intent of the parties, indications of credit deterioration and whether the markets in which TEC transacts have experienced dislocation. At Sept. 30, 2014, the fair value of derivatives was not materially affected by nonperformance risk. There were no Level 3 assets or liabilities for the periods presented.

Variable_Interest_Entities

Variable Interest Entities	9 Months Ended
Variable Interest Entities	Sep. 30, 2014
Variable Interest Entities	'
	14. Variable Interest Entities
	In the determination of a VIE’s primary beneficiary, the primary beneficiary is the enterprise that has both 1) the power to direct the activities of a VIE that most significantly impact the entity’s economic performance and 2) the obligation to absorb losses of the entity that could potentially be significant to the VIE or the right to receive benefits from the entity that could potentially be significant to the VIE.
	TEC has entered into multiple PPAs with wholesale energy providers in Florida to ensure the ability to meet customer energy demand and to provide lower cost options in the meeting of this demand. These agreements range in size from 117 MW to 160 MW of available capacity, are with similar entities and contain similar provisions. Because some of these provisions provide for the transfer or sharing of a number of risks inherent in the generation of energy, these agreements meet the definition of being VIEs. These risks include: operating and maintenance, regulatory, credit, commodity/fuel and energy market risk. TEC has reviewed these risks and has determined that the owners of these entities have retained the majority of these risks over the expected life of the underlying generating assets, have the power to direct the most significant activities, the obligation or right to absorb losses or benefits and hence remain the primary beneficiaries. As a result, TEC is not required to consolidate any of these entities. TEC purchased $8.1 million and $20.9 million of capacity pursuant to PPAs for the three and nine months ended Sept. 30, 2014, respectively, and $6.5 million and $16.4 million for the three and nine months ended Sept. 30, 2013, respectively.
	The company does not provide any material financial or other support to any of the VIEs it is involved with, nor is the company under any obligation to absorb losses associated with these VIEs. In the normal course of business, the company’s involvement with these VIEs does not affect its Consolidated Condensed Balance Sheets, Statements of Income or Cash Flows.
Tampa Electric Company [Member]	'
Variable Interest Entities	'
	13. Variable Interest Entities
	In the determination of a VIE’s primary beneficiary, the primary beneficiary is the enterprise that has both 1) the power to direct the activities of a VIE that most significantly impact the entity’s economic performance and 2) the obligation to absorb losses of the entity that could potentially be significant to the VIE or the right to receive benefits from the entity that could potentially be significant to the VIE.
	TEC has entered into multiple PPAs with wholesale energy providers in Florida to ensure the ability to meet customer energy demand and to provide lower cost options in the meeting of this demand. These agreements range in size from 117 MW to 160 MW of available capacity, are with similar entities and contain similar provisions. Because some of these provisions provide for the transfer or sharing of a number of risks inherent in the generation of energy, these agreements meet the definition of being VIEs. These risks include: operating and maintenance, regulatory, credit, commodity/fuel and energy market risk. TEC has reviewed these risks and has determined that the owners of these entities have retained the majority of these risks over the expected life of the underlying generating assets, have the power to direct the most significant activities, the obligation or right to absorb losses or benefits and hence remain the primary beneficiaries. As a result, TEC is not required to consolidate any of these entities. TEC purchased $8.1 million and $20.9 million of capacity pursuant to PPAs for the three and nine months ended Sept. 30, 2014, respectively, and $6.5 million and $16.4 million for the three and nine months ended Sept. 30, 2013, respectively.
	TEC does not provide any material financial or other support to any of the VIEs it is involved with, nor is TEC under any obligation to absorb losses associated with these VIEs. In the normal course of business, TEC’s involvement with these VIEs does not affect its Consolidated Condensed Balance Sheets, Statements of Income or Cash Flows.

Discontinued_Operations_Assets

Discontinued Operations, Assets Held for Sale and Asset Impairments Sale	9 Months Ended
	Sep. 30, 2014
Discontinued Operations And Disposal Groups [Abstract]	'
Discontinued Operations, Assets Held for Sale and Asset Impairments Sale	'
	15. Discontinued Operations, Assets Held for Sale and Asset Impairments
	TECO Coal Company
	On Sept. 29, 2014, the Board of Directors of TECO Energy authorized management to enter into negotiations for the sale of TECO Coal. As a result, the TECO Coal segment was accounted for as an asset held for sale and discontinued operation at Sept. 30, 2014, which for the quarter includes TECO Coal’s operating results and a pretax $98.4 million impairment charge related to the held-for-sale TECO Coal assets. This charge represents the write down to TECO Coal’s implied fair value of the binding offer less estimated costs to sell. Although the offer is a binding offer, the fair value measurement is considered a Level 2 measurement since the market is not active as defined by accounting standards (i.e. transactions for these assets are too infrequent to provide pricing information on an ongoing basis).
	As reported in Note 18, on Oct. 17, 2014, TECO Diversified entered into an SPA to sell all of its ownership interest in TECO Coal to Cambrian Coal Corporation for $120 million plus contingent payments of up to $50 million that may be paid between 2015 and 2019 depending on specified coal benchmark prices. The SPA also contains indemnification provisions subject to specified limitations as to time and amount. Closing on the sale is subject to the purchaser obtaining financing, and other normal closing conditions. After closing, TECO Energy will not have influence over operations of TECO Coal, therefore the contingent payments and indemnification provisions are not considered direct cash flows. The resulting sale price reflected in the SPA did not materially change from implied fair value of the binding offer.
	The following table provides a summary of the carrying amounts of the significant assets and liabilities reported in the combined current and non-current “Assets held for sale” and “Liabilities associated with assets held for sale” line items:

	Assets held for sale
	(millions)	30-Sep-14
	Current assets	$	133.7
	Property, plant and equipment, net and other long-term assets		78.6
	Total assets held for sale	$	212.3

	Liabilities associated with assets held for sale
	(millions)
	Current liabilities	$	41.1
	Long-term liabilities		64.4
	Total liabilities associated with assets held for sale	$	105.5
	TECO Guatemala
	In 2012, TECO Guatemala completed the sale of its interests in the Alborada and San José power stations, and related solid fuel handling and port facilities in Guatemala. All periods have been adjusted to reflect the reclassification of results from operations to discontinued operations for TECO Guatemala and certain charges at Parent that directly relate to TECO Guatemala. Additionally, in March 2014, an indemnification provision for an uncertain tax position at TCAE that was provided for in the 2012 purchase agreement was reversed due to favorable final decision by the highest court in Guatemala, resulting in the income from operations amount shown in the table below.
	Combined Components of Discontinued Operations
	The following table provides selected components of discontinued operations related to the sales of TECO Coal and TECO Guatemala:

	Components of income from discontinued operations	Three months ended						Nine months ended
		Sep 30,						Sep 30,
	(millions)	2014			2013			2014			2013
	Revenues	$	101.6		$	123.7		$	328.3		$	370
	(Loss) Income from operations (1)		(0.4	)		(2.9	)		0.8			0
	(Loss) on impairment		(98.4	)		0			(98.4	)		0
	(Loss) Income from discontinued operations (2)		(98.8	)		(2.9	)		(97.6	)		0
	(Benefit) Provision for income taxes (3)		(36.9	)		(1.4	)		(38.2	)		(2.4	)
	(Loss) Income from discontinued operations, net	$	(61.9	)	$	(1.5	)	$	(59.4	)	$	2.4

	-1	TECO Guatemala related amounts included above are $(0.2) million and $5.0 million during the three months ended Sept. 30, 2013 and nine months ended Sept. 30, 2014, respectively. Other periods have no reportable amount.
	-2	TECO Guatemala related amounts included above are $(0.2) million and $5.0 million during the three months ended Sept. 30, 2013 and nine months ended Sept. 30, 2014, respectively. Other periods have no reportable amount.
	-3	TECO Guatemala related amounts included above are $(0.1) million and $1.9 million during the three months ended Sept. 30, 2013 and nine months ended Sept. 30, 2014, respectively. Other periods have no reportable amount.

Acquisition_of_New_Mexico_Gas_

Acquisition of New Mexico Gas Intermediate	9 Months Ended
Acquisition of New Mexico Gas Intermediate	Sep. 30, 2014
Business Combinations [Abstract]	'
Acquisition of New Mexico Gas Intermediate	'
	16. Acquisition of New Mexico Gas Intermediate
	Description of Transaction
	On Sept. 2, 2014, the company completed the acquisition contemplated by the SPA dated May 25, 2013 by and among the company, NMGI, and Continental Energy Systems LLC. As a result of that acquisition, the company acquired all of the capital stock of NMGI. NMGI is the parent company of NMGC. The aggregate purchase price was $950 million, which included the assumption of $200 million of senior secured notes at NMGC, plus certain working capital adjustments.
	Description of NMGC
	NMGC, with approximately 720 employees, serves more than 513,000 customers, predominately residential, in New Mexico with the majority located in the Central Rio Grande Corridor region, which is one of the fastest growing regions in the state. The company serves approximately 60 percent of the state’s population with customers in 23 of New Mexico’s 33 counties. Customers are served through a combination of approximately 1,600 miles of transmission pipeline and 10,000 miles of distribution lines.
	Strategic Rationale for Acquisition
	—	A transformative transaction that immediately added more than 513,000 customers in a single state.
	—	Provides an opportunity for TECO’s experienced management team to share marketing expertise to a new and growing service territory, and for both companies to share best practices to support growth.
	—	Increases the percentage of net income from regulated operations and diversifies TECO Energy’s operating footprint.
	—	Provides immediate to near-term shareholder and customer benefits through organic growth opportunities.
	Acquisition-Related Regulatory Matters
	NMGC is a rate-regulated natural gas utility subject to the regulation of the NMPRC, including with respect to its rates, service standards, accounting, securities issuances, construction of major new transmission and distribution facilities and other matters affecting, directly or indirectly, the provision of natural gas sales and transportation services to NMGC’s customers.
	In May 2014, TECO Energy reached a settlement with the New Mexico Industrial Energy Consumers (which represents large customers), the New Mexico Attorney General’s office (which represents the New Mexico residential and small business customers) and the U.S. Department of Energy. As part of this settlement of the application for approval of the acquisition by the NMPRC, TECO Energy agreed, among other things, to:
	—	Freeze rates for NMGC customers until the end of 2017,
	—	credit NMGC customers with a $2 million rate credit to customer bills in the first year after the close of the transaction, which will increase to $4 million per year until NMGC’s next rate case,
	—	cap job losses in New Mexico at 99 over three years, many of which will be through attrition,
	—	maintain the NMGC name and headquarters in Albuquerque,
	—	support new economic development opportunities designed to attract new businesses to New Mexico through maintaining good service and reasonable customer rates,
	—	maintain or increase NMGC’s current level of community involvement and support, and
	—	own NMGC for at least 10 years.
	On Aug. 13, 2014, the NMPRC approved the acquisition with the conditions set forth in the settlement agreements described above. The transaction closed on Sept. 2, 2014.
	Purchase Price
	The total consideration in the acquisition was as follows:

	Consideration Transferred
	(millions)
	Cash	$	530.1
	Long-term debt assumed or settled, including accrued interest and fees		419.9
	Total consideration transferred, excluding cash and working capital adjustments	$	950
	Purchase Price Allocation
	The majority of NMGI’s assets acquired and liabilities assumed relate to deferred income taxes associated with its NOL. These were recorded in accordance with the applicable accounting guidance. Additionally, the company paid off the existing outstanding debt at NMGI and issued $200 million of new NMGI debt at closing. Since the refinancing took place at closing, face value approximated fair value.
	The majority of NMGC’s operations are subject to the rate-setting authority of the FERC and NMPRC and are accounted for pursuant to U.S. GAAP, including the accounting guidance for regulated operations. Rate-setting and cost recovery provisions currently in place for NMGC’s regulated operations provide revenues derived from costs, including a return on investment of assets and liabilities included in rate base. Except for long-term debt, the ARO, derivatives, OPEB plans, and deferred taxes, fair values of tangible and intangible assets and liabilities subject to these rate-setting provisions approximate their carrying values. Accordingly, assets acquired and liabilities assumed and pro-forma financial information do not reflect any net adjustments related to these amounts. The difference between fair value and pre-merger carrying amounts for long-term debt, derivatives, and the OPEB plan for regulated operations were recorded as regulatory assets or liabilities.
	The excess of the purchase price over the estimated fair values of assets acquired and liabilities assumed was recognized as goodwill at the acquisition date. The goodwill reflects the value paid primarily for opportunities for growth, synergies and an improved risk profile. Goodwill resulting from the acquisition was allocated entirely to the NMGC segment. Goodwill of $146.1 million related to the formation of NMGC in 2009 is tax deductible. The incremental goodwill recognized as part of this transaction is not deductible for income tax purposes, and as such, no deferred taxes will be recorded related to this portion of the goodwill.
	The initial accounting for the acquisition of NMGI is not complete because the valuations necessary to assess the fair values of certain assets acquired and liabilities assumed are considered preliminary as a result of the short time period between the closing of the acquisition and the end of the quarter. The allocation of the purchase price may be modified up to one year from the date of the acquisition, as more information is obtained about the fair value of assets acquired and liabilities assumed; however, the company expects to finalize these amounts by the end of 2014. The significant assets and liabilities for which preliminary valuation amounts are recognized at Sept. 30, 2014 include the fair value of contingencies and intangible assets and liabilities. The preliminary amounts recognized are subject to revision until the valuations are completed and to the extent that additional information is obtained about the facts and circumstances that existed as of the acquisition date. Any changes to the fair value assessments may affect the purchase price allocation and material changes could require the financial statements to be retroactively amended.
	The preliminary purchase price allocation of the acquisition of NMGI and NMGC is as follows:

	Preliminary Purchase Price Allocation
	(millions)
	Current assets (a)	$	48.7
	Property, plant and equipment		618.9
	OPEB regulatory asset		6.4
	Debt-related regulatory asset		23.9
	Goodwill		401.8
	Deferred tax assets		52.8
	Other assets		30.2
	Total assets	$	1,182.70
	Current liabilities	$	(35.0	)
	Long-term debt fair value adjustment and interest assumed		(22.7	)
	Cost of removal regulatory liability		(100.6	)
	Deferred tax liabilities		(60.8	)
	OPEB liability		(9.8	)
	Deferred credits and other liabilities		(3.8	)
	Total liabilities	$	(232.7	)
	Total purchase price allocation, excluding cash and working capital adjustments	$	950


	(a)	Includes accounts receivables with fair value of $18.9 million, gross contract value of $19.6 million, and $0.7 million of contractual receivables not expected to be collected.
	Current Quarter and Year-to-Date Impact of Acquisition
	The impact of NMGI and NMGC on the company’s revenues in the Consolidated Statements of Operations for the three months and nine months ended Sept. 30, 2014 was an increase of $16.2 million. The impact of NMGI and NMGC on the company’s net income in the Consolidated Statements of Operations for the three months and nine months ended Sept. 30, 2014 was a decrease of $2.0 million.
	Pro Forma Impact of the Acquisition
	The following unaudited pro forma financial information reflects the consolidated results of operations of the company and reflects the amortization of purchase accounting adjustments assuming the acquisition had taken place on Jan. 1, 2013. The unaudited pro forma financial information has been presented for illustrative purposes only and is not necessarily indicative of the consolidated results of operations that would have been achieved or the future consolidated results of operations of the company. This information is preliminary in nature and subject to change based on final purchase price adjustments.
	Pro forma earnings presented below include adjustments related to non-recurring acquisition consummation, integration and other costs incurred by the company during the period. After-tax non-recurring acquisition consummation, integration and other costs incurred by the company were $0.9 million and $5.7 million, respectively, for the three and nine months ended Sept. 30, 2014, and $2.1 million and $3.9 million, respectively, for the three and nine months ended Sept. 30, 2013. The pro forma financial information also excludes potential future cost savings or non-recurring charges related to the acquisition.

Pro Forma Impact of Acquisition	Three months ended Sep 30,						Nine months ended Sep 30,
(millions, except per share amounts)	2014				2013		2014			2013
Revenues	$	720			$	684.5	$	2,111.00		$	2,024.10
Net income from continuing operations	$	70.8			$	64.9	$	199.3		$	171.4
Basic and Diluted EPS from continuing operations	$	0.31			$	0.28	$	0.86		$	0.74
Intangible Assets Recorded

Goodwill
(millions)	NMGC				Total
Balance as of Jul 1, 2014	$	0			$	0
Goodwill acquired in business acquisition		401.8			$	401.8
Balance as of Sep 30, 2014	$	401.8			$	401.8

Goodwill resulting from the acquisition was allocated entirely to the NMGC segment. The goodwill related to the formation of NMGC in 2009 in the amount of $146.1 million is tax deductible. The incremental goodwill recognized of $255.7 million is not deductible for income tax purposes, and as such, no deferred taxes will be recorded related to this portion of the goodwill.
Many of NMGC’s transmission and distribution facilities are located on lands that require the grant of rights-of-way or franchises (collectively, “ROW”) from non-tribal governmental entities, Native American Tribes and Pueblos, or private landowners. Historically, ROW costs have been recovered in rates charged to customers, and NMGC will continue to seek to recover ROW costs in future rates charged to customers. However, TECO Energy has agreed to freeze rates for NMGC’s customers until Dec. 31, 2017 as a condition to the acquisition.
The company’s intangible assets and liabilities acquired through the acquisition of NMGI included in its Consolidated Condensed Balance Sheets, along with the future estimated amortization, were as follows as of Sept. 30, 2014:

Description	Weighted average amortization (years) (a)				Gross		Accumulated amortization			Net		2014		2015		2016		2017		2018		2019 and beyond
Rights-of-way		17			$	27.2	$	(0.1	)	$	27.1	$	0.3	$	1.4	$	1.4	$	1.4	$	1.4	$	21.2

(a)	Weighted average amortization period was calculated as of the date of acquisition.
Transaction and Integration Costs
The following after-tax transaction and integration charges were recognized in connection with the acquisition and are included in the TECO Energy Consolidated Statements of Operations for the nine months ended Sept. 30, 2014.

Transaction and Integration Costs	Total
(millions)
Legal and other consultants	$	7.2
Bridge loan costs		2.9
Employee expenses		0.2
Severance and relocation costs		1.7
Other costs and tax benefit		(4.5	)
Total accounting charges	$	7.5
The company has an ongoing severance plan under which, in general, the longer a terminated employee worked prior to termination, the greater the amount of severance benefits. The company records a liability and expense or regulatory asset for severance once terminations are probable of occurrence and the related severance benefits can be reasonably estimated. For severance benefits that are incremental to its ongoing severance plan (“one-time termination benefits”), the company measures the obligation and records the expense at its fair value at the communication date if there are no future service requirements, or, if future service is required to receive the termination benefit, ratably over the required service period.
In conjunction with the acquisition, in September 2014, TECO Energy and NMGC each offered a severance plan to certain eligible employees. Severance costs incurred were recorded primarily within Operation and maintenance other expense in the Consolidated Condensed Statements of Income. Cash payments under the severance plan began in the third quarter of 2014 and will continue through 2015. Substantially all cash payments under the plan are expected to be made by the end 2015 resulting in the substantial completion of the acquisition integration plan. As of Sept. 30, 2014, the obligations associated with the severance benefits costs are $2.2 million.

Common_Stock

Common Stock	9 Months Ended
Common Stock	Sep. 30, 2014
Equity [Abstract]	'
Common Stock	'


	17. Common Stock
	Public Offering of 15.5 million in Common Shares
	On July 1, 2014, the company entered into an underwriting agreement with Morgan Stanley & Co. LLC, as representative of the several underwriters named therein, pursuant to which the company agreed to offer and sell 15.5 million shares of its common stock in an underwritten public offering at a public offering price of $18.10 per share. The company received approximately $271 million in net proceeds from the offering after underwriting fees and offering expenses. The shares were delivered to the underwriters on July 8, 2014.
	Pursuant to the terms of the underwriting agreement, the company granted the underwriters a 30-day option to purchase up to an additional 2.3 million shares. The company received approximately $21 million of net proceeds when the underwriters exercised this option for an additional 1.2 million shares.
	The company used the net proceeds from the offering to fund, in part, the acquisition of NMGI and for general corporate purposes.

Subsequent_Events

Subsequent Events	9 Months Ended
Subsequent Events	Sep. 30, 2014
Subsequent Events [Abstract]	'
Subsequent Events	'
	18. Subsequent Events
	Sale of TECO Coal Corporation
	On Oct. 17, 2014, TECO Diversified entered into an SPA to sell all of its ownership interest in TECO Coal to Cambrian Coal Corporation for $120 million, subject to a working capital adjustment, plus contingent payments of up to $50 million that may be paid between 2015 and 2019 depending on specified coal benchmark prices. The SPA provides for TECO Coal to reorganize as a limited liability company prior to closing and for Cambrian Coal Corporation to acquire all of the membership interests in that limited liability company. Initial net proceeds from the sale (not including any contingent payments) are expected to be used to repay short-term debt of TECO Energy and for general corporate purposes.
	The SPA contains customary representations, warranties, covenants, and closing conditions, including the purchaser’s obtaining debt financing in order to pay a portion of the purchase price. The SPA also contains indemnification provisions subject to specified limitations as to time and amount. In addition, the SPA is subject to termination by either party if specified closing conditions are not met by Dec. 31, 2014.
	NMPRC Approval of Amendments to the New Mexico Gas Company 2011 Notes
	On Feb. 8, 2011, NMGC issued secured notes in an aggregate principal amount of $200 million (NMGC 2011 Notes), maturing Feb. 8, 2021. The NMGC 2011 Notes were issued in a private placement that was not subject to the registration requirements of the Securities Act of 1933. On July 16, 2014, NMGC received approvals from the noteholders of the NMGC 2011 Notes to release the collateral securing the NMGC 2011 Notes by amending the existing note purchase agreement. The amendments to the note purchase agreement were subject to the approval of the NMPRC and on Oct. 22, 2014, NMGC received the required NMPRC approval of the amendments. On Oct. 27, 2014, the amendments became effective and the collateral securing the NMGC 2014 Notes was released.

Summary_of_Significant_Account1

Summary of Significant Accounting Policies (Policies)	9 Months Ended
Summary of Significant Accounting Policies (Policies)	Sep. 30, 2014
Principles of Consolidation and Basis of Presentation	'
	Principles of Consolidation and Basis of Presentation
	All significant intercompany balances and intercompany transactions have been eliminated in consolidation. In the opinion of management, the unaudited consolidated condensed financial statements include all adjustments that are of a recurring nature and necessary to state fairly the financial position of TECO Energy, Inc. and its subsidiaries as of Sept. 30, 2014 and Dec. 31, 2013, and the results of operations and cash flows for the periods ended Sept. 30, 2014 and 2013. The results of operations for the three months and nine months ended Sept. 30, 2014 are not necessarily indicative of the results that can be expected for the entire fiscal year ending Dec. 31, 2014.
	The unaudited consolidated condensed financial statements include NMGI and NMGC as of the acquisition date of Sept. 2, 2014 (see Note 16). In addition, all periods have been adjusted to reflect the reclassification of results from operations to discontinued operations for TECO Coal and certain charges at Parent that directly related to TECO Coal (see Note 15).
	The use of estimates is inherent in the preparation of financial statements in accordance with U.S. GAAP. Actual results could differ from these estimates. The year-end consolidated condensed balance sheet data was derived from audited financial statements, however, this quarterly report on Form 10-Q does not include all year-end disclosures required for an annual report on Form 10-K by U.S. GAAP.
Revenues	'
	Revenues
	As of Sept. 30, 2014 and Dec. 31, 2013, unbilled revenues of $61.0 million and $46.7 million, respectively, are included in the “Receivables” line item on the Consolidated Condensed Balance Sheets.
Accounting for Excise Taxes, Franchise Fees and Gross Receipts	'
	Accounting for Excise Taxes, Franchise Fees and Gross Receipts
	TECO Coal incurs most of TECO Energy’s total excise taxes, which are accrued as an expense and reconciled to the actual cash payment of excise taxes. As general expenses, they are not specifically recovered through revenues. Excise taxes paid by the regulated utilities are not material and are expensed when incurred.
	Tampa Electric and PGS are allowed to recover certain costs on a dollar-per-dollar basis incurred from customers through prices approved by the FPSC. The amounts included in customers’ bills for franchise fees and gross receipt taxes are included as revenues on the Consolidated Condensed Statements of Income. Franchise fees and gross receipt taxes payable by the regulated utilities are included as an expense on the Consolidated Condensed Statements of Income in “Taxes, other than income”. These amounts totaled $31.7 million and $86.7 million, respectively, for the three and nine months ended Sept. 30, 2014, compared to $29.7 million and $81.8 million, respectively, for the three and nine months ended Sept. 30, 2013.
Cash Flows Related to Derivatives and Hedging Activities	'
	Cash Flows Related to Derivatives and Hedging Activities
	The company classifies cash inflows and outflows related to derivative and hedging instruments in the appropriate cash flow sections associated with the item being hedged. In the case of diesel fuel swaps, which are used to mitigate the fluctuations in the price of diesel fuel, the cash inflows and outflows are included in the operating section. For natural gas and ongoing interest rate swaps, the cash inflows and outflows are included in the operating section. For interest rate swaps that settle coincident with the debt issuance, the cash inflows and outflows are treated as premiums or discounts and included in the financing section of the Consolidated Condensed Statements of Cash Flows.
Goodwill	'
	Goodwill
	Goodwill represents the excess of the purchase price over the value assigned to the net identifiable assets of businesses acquired. Accounting guidance requires that the company perform impairment tests on its goodwill annually or at any time when events occur that could impact the value of the company’s goodwill. If an impairment test of goodwill shows that the carrying amount of the goodwill is in excess of the fair value, a corresponding impairment loss would be recorded in the Statements of Operations. The company added goodwill during the quarter resulting from the NMGC acquisition (see Note 16).
Tampa Electric Company [Member]	'
Principles of Consolidation and Basis of Presentation	'
	Principles of Consolidation and Basis of Presentation
	TEC is a wholly-owned subsidiary of TECO Energy, Inc. For the purposes of its consolidated financial reporting, TEC is comprised of the electric division, generally referred to as Tampa Electric, the natural gas division, generally referred to as PGS, and potentially the accounts of VIEs for which it is the primary beneficiary. For the periods presented, no VIEs have been consolidated (see Note 13).
	All significant intercompany balances and intercompany transactions have been eliminated in consolidation. In the opinion of management, the unaudited consolidated condensed financial statements include all adjustments that are of a recurring nature and necessary to state fairly the financial position of TEC as of Sept. 30, 2014 and Dec. 31, 2013, and the results of operations and cash flows for the periods ended Sept. 30, 2014 and 2013. The results of operations for the three and nine months ended Sept. 30, 2014 are not necessarily indicative of the results that can be expected for the entire fiscal year ending Dec. 31, 2014.
	The use of estimates is inherent in the preparation of financial statements in accordance with U.S. GAAP. Actual results could differ from these estimates. The year-end consolidated condensed balance sheet data was derived from audited financial statements, however, this quarterly report on Form 10-Q does not include all year-end disclosures required for an annual report on Form 10-K by U.S. GAAP.
Revenues	'
	Revenues
	As of Sept. 30, 2014 and Dec. 31, 2013, unbilled revenues of $53.3 million and $46.7 million, respectively, are included in the “Receivables” line item on the Consolidated Condensed Balance Sheets.
Accounting for Excise Taxes, Franchise Fees and Gross Receipts	'
	Accounting for Excise Taxes, Franchise Fees and Gross Receipts
	The regulated utilities are allowed to recover certain costs on a dollar-per-dollar basis incurred from customers through prices approved by the FPSC. The amounts included in customers’ bills for franchise fees and gross receipt taxes are included as revenues on the Consolidated Condensed Statements of Income. Franchise fees and gross receipt taxes payable by the regulated utilities are included as an expense on the Consolidated Condensed Statements of Income in “Taxes, other than income”. These amounts totaled $31.7 million and $86.7 million, respectively, for the three and nine months ended Sept. 30, 2014, compared to $29.7 million and $81.8 million, respectively, for the three and nine months ended Sept. 30, 2013.
Cash Flows Related to Derivatives and Hedging Activities	'
	Cash Flows Related to Derivatives and Hedging Activities
	TEC classifies cash inflows and outflows related to derivative and hedging instruments in the appropriate cash flow sections associated with the item being hedged. For natural gas and ongoing interest rate swaps, the cash inflows and outflows are included in the operating section. For interest rate swaps that settle coincident with the debt issuance, the cash inflows and outflows are treated as premiums or discounts and included in the financing section of the Consolidated Condensed Statements of Cash Flows.

Regulatory_Tables

Regulatory (Tables)	9 Months Ended
Regulatory (Tables)	Sep. 30, 2014
Schedule of Regulatory Assets and Regulatory Liabilities	'
	Details of the regulatory assets and liabilities as of Sept. 30, 2014 and Dec. 31, 2013 are presented in the following table:

	Regulatory Assets and Liabilities
	(millions)	30-Sep-14		31-Dec-13
	Regulatory assets:
	Regulatory tax asset (1)	$	69.1	$	67.4
	Other:
	Cost-recovery clauses		9.3		6.1
	Postretirement benefit asset (2)		194.1		182.7
	Deferred bond refinancing costs (3)		9.2		8
	Debt basis adjustment (3)		21.7		0
	Environmental remediation		52.3		51.4
	Competitive rate adjustment		2.6		4.1
	Other		8.2		7.7
	Total other regulatory assets		297.4		260
	Total regulatory assets		366.5		327.4
	Less: Current portion		24.3		34.3
	Long-term regulatory assets	$	342.2	$	293.1
	Regulatory liabilities:
	Regulatory tax liability (1)	$	6.7	$	9.8
	Other:
	Cost-recovery clauses		34.6		54.5
	Transmission and delivery storm reserve		56.1		56.1
	Deferred gain on property sales (4)		1.1		2
	Accumulated reserve - cost of removal		693.6		594
	Other		0.9		0.8
	Total other regulatory liabilities		786.3		707.4
	Total regulatory liabilities		793		717.2
	Less: Current portion		65.8		85.8
	Long-term regulatory liabilities	$	727.2	$	631.4
	-1	Primarily related to plant life and derivative positions.
	-2	Amortized over remaining service life of plan participants.
	-3	Amortized over the term of the related debt instruments.
	-4	Amortized over a 5-year period with various ending dates.
Regulatory Assets and Related Recovery Period	'
	All regulatory assets are recovered through the regulatory process. The following table further details the regulatory assets and the related recovery periods:

	Regulatory Assets
		Sep 30,		Dec 31,
	(millions)	2014		2013
	Clause recoverable (1)	$	11.9	$	10.2
	Components of rate base (2)		199.3		185.6
	Regulatory tax assets (3)		69.1		67.4
	Capital structure and other (3)		86.2		64.2
	Total	$	366.5	$	327.4
	-1	To be recovered through cost-recovery mechanisms approved by the FPSC on a dollar-for-dollar basis in the next year.
	-2	Primarily reflects allowed working capital, which is included in rate base and earns a rate of return as permitted by the FPSC.
	-3	“Regulatory tax assets” and “Capital structure and other” regulatory assets have a recoverable period longer than a fiscal year and are recognized over the period authorized by the regulatory agency. Also included are unamortized loan costs, which are amortized over the life of the related debt instruments. See footnotes 1 and 2 in the prior table for additional information.
Tampa Electric Company [Member]	'
Schedule of Regulatory Assets and Regulatory Liabilities	'


	Details of the regulatory assets and liabilities as of Sept. 30, 2014 and Dec. 31, 2013 are presented in the following table:

	Regulatory Assets and Liabilities
	(millions)	30-Sep-14		31-Dec-13
	Regulatory assets:
	Regulatory tax asset (1)	$	68.6	$	67.4
	Other:
	Cost-recovery clauses		8		6.1
	Postretirement benefit asset (2)		187.8		182.7
	Deferred bond refinancing costs (3)		7.4		8
	Environmental remediation		52.3		51.4
	Competitive rate adjustment		2.6		4.1
	Other		7.9		7.7
	Total other regulatory assets		266		260
	Total regulatory assets		334.6		327.4
	Less: Current portion		22.9		34.3
	Long-term regulatory assets	$	311.7	$	293.1
	Regulatory liabilities:
	Regulatory tax liability (1)	$	5.3	$	9.8
	Other:
	Cost-recovery clauses		33.1		54.5
	Transmission and delivery storm reserve		56.1		56.1
	Deferred gain on property sales (4)		1.1		2
	Accumulated reserve - cost of removal		591.5		594
	Other		0.9		0.8
	Total other regulatory liabilities		682.7		707.4
	Total regulatory liabilities		688		717.2
	Less: Current portion		64.5		85.8
	Long-term regulatory liabilities	$	623.5	$	631.4
	-1	Primarily related to plant life and derivative positions.
	-2	Amortized over the remaining service life of plan participants.
	-3	Amortized over the term of the related debt instruments.
	-4	Amortized over a 5-year period with various ending dates.
Regulatory Assets and Related Recovery Period	'
	All regulatory assets are recovered through the regulatory process. The following table further details the regulatory assets and the related recovery periods:

	Regulatory Assets
		Sep 30,		Dec 31,
	(millions)	2014		2013
	Clause recoverable (1)	$	10.6	$	10.2
	Components of rate base (2)		190.9		185.6
	Regulatory tax assets (3)		68.6		67.4
	Capital structure and other (3)		64.5		64.2
	Total	$	334.6	$	327.4
	-1	To be recovered through cost-recovery mechanisms approved by the FPSC on a dollar-for-dollar basis in the next year.
	-2	Primarily reflects allowed working capital, which is included in rate base and earns a rate of return as permitted by the FPSC.
	-3	“Regulatory tax assets” and “Capital structure and other” regulatory assets have a recoverable period longer than a fiscal year and are recognized over the period authorized by the regulatory agency. Also included are unamortized loan costs, which are amortized over the life of the related debt instruments. See footnotes 1 and 2 in the prior table for additional information.

Employee_Postretirement_Benefi1

Employee Postretirement Benefits (Tables)	9 Months Ended
Employee Postretirement Benefits (Tables)	Sep. 30, 2014
Compensation And Retirement Disclosure [Abstract]	'
Schedule of Net Periodic Benefit Cost	'
	Included in the table below is the periodic expense for pension and other postretirement benefits offered by the company.

	Pension Expense
	(millions)	Pension Benefits						Other Postretirement Benefits
	Three months ended Sep 30,	2014			2013			2014			2013
	Components of net periodic benefit expense
	Service cost	$	4.6		$	4.5		$	0.6		$	0.7
	Interest cost on projected benefit obligations		8			7.3			2.7			2.3
	Expected return on assets		(10.5	)		(9.6	)		(0.1	)		0
	Amortization of:
	Prior service (benefit) cost		(0.1	)		(0.1	)		0			(0.1	)
	Actuarial loss		3.3			5.1			0			0.2
	Regulatory asset		0			0			0.1			0
	Settlement cost		0			1			0			0
	Net pension expense recognized in the	$	5.3		$	8.2		$	3.3		$	3.1
	TECO Energy Consolidated Condensed Statements of Income	$	5.3		$	8.2		$	3.3		$	3.1
	Nine months ended Sep 30,
	Components of net periodic benefit expense
	Service cost	$	12.9		$	13.6		$	1.8		$	1.9
	Interest cost on projected benefit obligations		24.4			21.7			7.9			7
	Expected return on assets		(31.2	)		(28.8	)		(0.1	)		0
	Amortization of:
	Prior service (benefit) cost		(0.3	)		(0.3	)		(0.1	)		(0.3	)
	Actuarial loss		10			15.4			0.1			0.7
	Regulatory asset		0			0			0.1			0
	Settlement cost		0			1			0			0
	Net pension expense recognized in the	$	15.8		$	22.6		$	9.7		$	9.3
	TECO Energy Consolidated Condensed Statements of Income	$	15.8		$	22.6		$	9.7		$	9.3

ShortTerm_Debt_Tables

Short-Term Debt (Tables)	9 Months Ended
Short-Term Debt (Tables)	Sep. 30, 2014
Short-Term Debt Credit Facilities	'
	At Sept. 30, 2014 and Dec. 31, 2013, the following credit facilities and related borrowings existed:

	Credit Facilities
		30-Sep-14						31-Dec-13
						Letters						Letters
		Credit		Borrowings		of Credit		Credit		Borrowings		of Credit
	(millions)	Facilities		Outstanding (1)		Outstanding		Facilities		Outstanding (1)		Outstanding
	Tampa Electric Company:
	5-year facility (2)	$	325	$	0	$	0.7	$	325	$	6	$	0.7
	1-year accounts		150		0		0		150		78		0
	receivable facility		150		0		0		150		78		0
	TECO Energy/TECO Finance:
	5-year facility (2)(3)		300		55		0		200		0		0
	New Mexico Gas Company:
	5-year facility (2)		125		17		1.7		0		0		0
	Total	$	900	$	72	$	2.4	$	675	$	84	$	0.7

	(1) Borrowings outstanding are reported as notes payable.
	(2) This 5-year facility matures Dec. 17, 2018.
	(3) TECO Finance is the borrower and TECO Energy is the guarantor of this facility.

Tampa Electric Company [Member]	'
Short-Term Debt Credit Facilities	'
	At Sept. 30, 2014 and Dec. 31, 2013, the following credit facilities and related borrowings existed:

	Credit Facilities
		30-Sep-14						31-Dec-13
						Letters						Letters
		Credit		Borrowings		of Credit		Credit		Borrowings		of Credit
	(millions)	Facilities		Outstanding (1)		Outstanding		Facilities		Outstanding (1)		Outstanding
	Tampa Electric Company:
	5-year facility (2)	$	325	$	0	$	0.7	$	325	$	6	$	0.7
	1-year accounts		150		0		0		150		78		0
	receivable facility		150		0		0		150		78		0
	Total	$	475	$	0	$	0.7	$	475	$	84	$	0.7
	-1	Borrowings outstanding are reported as notes payable.
	-2	This 5-year facility matures Dec. 17, 2018.

Other_Comprehensive_Income_Tab

Other Comprehensive Income (Tables)	9 Months Ended
Other Comprehensive Income (Tables)	Sep. 30, 2014
Other Comprehensive Income [Abstract]	'
Other Comprehensive Income	'
	TECO Energy reported the following OCI for the three and nine months ended Sept. 30, 2014 and 2013, related to changes in the fair value of cash flow hedges and amortization of unrecognized benefit costs associated with the company’s postretirement plans:

	Other Comprehensive Income
		Three months ended Sep 30,									Nine months ended Sep 30,
	(millions)	Gross			Tax			Net			Gross			Tax			Net
	2014
	Unrealized loss on cash flow hedges	$	(0.3	)	$	0.1		$	(0.2	)	$	(0.3	)	$	0.1		$	(0.2	)
	Reclassification from AOCI to net income (1)		0.4			(0.1	)		0.3			0.9			(0.3	)		0.6
	Gain on cash flow hedges		0.1			0			0.1			0.6			(0.2	)		0.4
	Amortization of unrecognized benefit costs (2)		0.4			(0.2	)		0.2			2.4			(0.8	)		1.6
	Increase in unrecognized postemployment costs (3)		0			0			0			(12.9	)		4.7			(8.2	)
	Change in benefit obligation due to remeasurement		(1.1	)		0.4			(0.7	)		(1.1	)		0.4			(0.7	)
	Total other comprehensive income (loss) from continuing operations	$	(0.6	)	$	0.2		$	(0.4	)	$	(11.0	)	$	4.1		$	(6.9	)
	2013
	Unrealized gain on cash flow hedges	$	1.1		$	(0.4	)	$	0.7		$	0.7		$	(0.3	)	$	0.4
	Reclassification from AOCI to net income (1)		0.1			0			0.1			1			(0.3	)		0.7
	Gain on cash flow hedges		1.2			(0.4	)		0.8			1.7			(0.6	)		1.1
	Amortization of unrecognized benefit costs (2)		1			(0.4	)		0.6			3.2			(1.2	)		2
	Recognized benefit costs due to settlement		2.6			(1.0	)		1.6			2.6			(1.0	)		1.6
	Total other comprehensive income from continuing operations	$	4.8		$	(1.8	)	$	3		$	7.5		$	(2.8	)	$	4.7
	(1) Related to interest rate contracts recognized in Interest expense and commodity contracts recognized in Loss from discontinued operations.
	(2) Related to postretirement and postemployment benefits. See Note 5 for additional information.
	(3) Amounts reflect an out-of-period adjustment related to TECO Coal's unfunded black lung liability.


	Other Comprehensive Income
	Other Comprehensive Income	Three months ended Sep 30,									Nine months ended Sep 30,
	(millions)	Gross			Tax			Net			Gross			Tax			Net
	2014
	Unrealized loss on cash flow hedges	$	0		$	0		$	0		$	0		$	0		$	0
	Reclassification from AOCI to net income		0.4			(0.1	)		0.3			0.8			(0.3	)		0.5
	Gain on cash flow hedges		0.4			(0.1	)		0.3			0.8			(0.3	)		0.5
	Total other comprehensive income	$	0.4		$	(0.1	)	$	0.3		$	0.8		$	(0.3	)	$	0.5
	2013
	Unrealized loss on cash flow hedges	$	0		$	0		$	0		$	0		$	0		$	0
	Reclassification from AOCI to net income		0.4			(0.2	)		0.2			1.1			(0.4	)		0.7
	Gain on cash flow hedges		0.4			(0.2	)		0.2			1.1			(0.4	)		0.7
	Total other comprehensive income	$	0.4		$	(0.2	)	$	0.2		$	1.1		$	(0.4	)	$	0.7


Accumulated Other Comprehensive Loss	'

	Accumulated Other Comprehensive Loss
	(millions)	30-Sep-14			31-Dec-13
	Unrecognized pension loss and prior service credit (1)	$	(19.9	)	$	(20.5	)
	Unrecognized other benefit loss, prior service cost and		7.2			15.1
	transition obligation (2)		7.2			15.1
	Net unrealized losses from cash flow hedges (3)		(7.4	)		(7.8	)
	Total accumulated other comprehensive loss	$	(20.1	)	$	(13.2	)

	(1) Net of tax benefit of $12.3 million and $12.6 million as of Sept. 30, 2014 and Dec. 31, 2013, respectively.
	(2) Net of tax expense of $4.4 million and $9.1 million as of Sept. 30, 2014 and Dec. 31, 2013, respectively. Balance includes a $7.8 million loss related to TECO Coal's unfunded black lung liability that will be reclassified from AOCI to net income from discontinued operations upon the settlement of the black lung obligation at the sale date. See Note 18.
	(3) Net of tax benefit of $4.7 million and $4.9 million as of Sept. 30, 2014 and Dec. 31, 2013, respectively.


	Accumulated Other Comprehensive Loss
	(millions)	30-Sep-14			31-Dec-13
	Net unrealized losses from cash flow	$	(7.3	)	$	(7.8	)
	hedges (1)	$	(7.3	)	$	(7.8	)
	Total accumulated other	$	(7.3	)	$	(7.8	)
	comprehensive loss	$	(7.3	)	$	(7.8	)
	-1	Net of tax benefit of $4.6 million and $4.9 million as of Sept. 30, 2014 and Dec. 31, 2013, respectively.

Earnings_Per_Share_Tables

Earnings Per Share (Tables)	9 Months Ended
Earnings Per Share (Tables)	Sep. 30, 2014
Earnings Per Share [Abstract]	'
Schedule of Earnings Per Share	'
		For the three months ended Sep 30,						For the nine months ended Sep 30,
	(millions, except per share amounts)	2014			2013 (1)			2014			2013 (1)
	Basic earnings per share
	Net income from continuing operations	$	73		$	64.3		$	179		$	153.3
	Amount allocated to nonvested participating shareholders		(0.2	)		(0.2	)		(0.6	)		(0.5	)
	Income before discontinued operations available to	$	72.8		$	64.1		$	178.4		$	152.8
	common shareholders - Basic	$	72.8		$	64.1		$	178.4		$	152.8
	Income (Loss) from discontinued operations, net	$	(61.9	)	$	(1.5	)	$	(59.4	)	$	2.4
	Amount allocated to nonvested participating shareholders		0			0			0			0
	Income (Loss) from discontinued operations available to	$	(61.9	)	$	(1.5	)	$	(59.4	)	$	2.4
	common shareholders - Basic	$	(61.9	)	$	(1.5	)	$	(59.4	)	$	2.4
	Net income	$	11.1		$	62.8		$	119.6		$	155.7
	Amount allocated to nonvested participating shareholders		(0.2	)		(0.2	)		(0.6	)		(0.5	)
	Net income available to common shareholders - Basic	$	10.9		$	62.6		$	119		$	155.2
	Average common shares outstanding - Basic		227.8			215.2			220.3			214.9
	Earnings per share from continuing operations available to	$	0.32		$	0.3		$	0.81		$	0.71
	common shareholders - Basic	$	0.32		$	0.3		$	0.81		$	0.71
	Earnings per share from discontinued operations available to	$	(0.28	)	$	(0.01	)	$	(0.27	)	$	0.01
	common shareholders - Basic	$	(0.28	)	$	(0.01	)	$	(0.27	)	$	0.01
	Earnings per share available to common shareholders - Basic	$	0.04		$	0.29		$	0.54		$	0.72
	Diluted earnings per share
	Net income from continuing operations	$	73		$	64.3		$	179		$	153.3
	Amount allocated to nonvested participating shareholders		(0.2	)		(0.2	)		(0.6	)		(0.5	)
	Income before discontinued operations available to	$	72.8		$	64.1		$	178.4		$	152.8
	common shareholders - Diluted	$	72.8		$	64.1		$	178.4		$	152.8
	Income (Loss) from discontinued operations, net	$	(61.9	)	$	(1.5	)	$	(59.4	)	$	2.4
	Amount allocated to nonvested participating shareholders		0			0			0			0
	Income (Loss) from discontinued operations available to	$	(61.9	)	$	(1.5	)	$	(59.4	)	$	2.4
	common shareholders - Diluted	$	(61.9	)	$	(1.5	)	$	(59.4	)	$	2.4
	Net income	$	11.1		$	62.8		$	119.6		$	155.7
	Amount allocated to nonvested participating shareholders		(0.2	)		(0.2	)		(0.6	)		(0.5	)
	Net income available to common shareholders - Diluted	$	10.9		$	62.6		$	119		$	155.2
	Unadjusted average common shares outstanding - Diluted		227.8			215.2			220.3			214.9
	Assumed conversion of stock options, unvested restricted stock and		0.5			0.4			0.5			0.5
	contingent performance shares, net		0.5			0.4			0.5			0.5
	Average common shares outstanding - Diluted		228.3			215.6			220.8			215.4
	Earnings per share from continuing operations available to	$	0.32		$	0.3		$	0.81		$	0.71
	common shareholders - Diluted	$	0.32		$	0.3		$	0.81		$	0.71
	Earnings per share from discontinued operations available to	$	(0.28	)	$	(0.01	)	$	(0.27	)	$	0.01
	common shareholders - Diluted	$	(0.28	)	$	(0.01	)	$	(0.27	)	$	0.01
	Earnings per share available to common shareholders - Diluted	$	0.04		$	0.29		$	0.54		$	0.72
	Anti-dilutive shares		0			0			0			0

	(1) All prior periods presented reflect the classification of TECO Coal as discontinued operations (see Note 15).

Commitments_and_Contingencies_

Commitments and Contingencies (Tables)	9 Months Ended
Commitments and Contingencies (Tables)	Sep. 30, 2014
Letters of Credit and Guarantees	'
	A summary of the face amount or maximum theoretical obligation and the year of expiration under letters of credit and guarantees as of Sept. 30, 2014 is as follows:

	Guarantees - TECO Energy
	(millions)	Year of expiration						Maximum
						After (1)		Theoretical		Liabilities Recognized
	Guarantees for the Benefit of:	2014		2015-2018		2018		Obligation		at Sep 30, 2014 (2)
	TECO Coal
	Fuel purchase related	$	0	$	0.7	$	4	$	4.7	$	0
	Other subsidiaries
	Fuel purchase/energy management		0		0		92.9		92.9		0.1
	Total	$	0	$	0.7	$	96.9	$	97.6	$	0.1

	Letters of Credit - Tampa Electric Company
	(millions)					After (1)				Liabilities Recognized
	Letters of Credit for the Benefit of:	2014		2015-2018		2018		Total		at Sep 30, 2014 (2)
	Tampa Electric Company	$	0	$	0	$	0.7	$	0.7	$	0.1

	Letters of Credit - New Mexico Gas Company
	(millions)					After (1)				Liabilities Recognized
	Letters of Credit for the Benefit of:	2014		2015-2018		2018		Total		at Sep 30, 2014 (2)
	New Mexico Gas Company	$	0	$	0	$	1.7	$	1.7	$	1.3

	(1) These letters of credit and guarantees renew annually and are shown on the basis that they will continue to renew beyond 2018.
	(2) The amounts shown are the maximum theoretical amounts guaranteed under current agreements. Liabilities recognized represent the associated obligation of TECO Energy or TEC or NMGC under these agreements at Sept. 30, 2014. The obligations under these letters of credit and guarantees include net accounts payable and net derivative liabilities.


Tampa Electric Company [Member]	'
Letters of Credit and Guarantees	'
	A summary of the face amount or maximum theoretical obligation under TEC’s letters of credit as of Sept. 30, 2014 is as follows:

	Letters of Credit - Tampa Electric Company
	(millions)					After (1)				Liabilities Recognized
	Letters of Credit for the Benefit of:	2014		2015-2018		2018		Total		at Sep 30, 2014
	Tampa Electric Company (2)	$	0	$	0	$	0.7	$	0.7	$	0.1
	-1	These letters of credit renew annually and are shown on the basis that they will continue to renew beyond 2018.
	-2	The amounts shown are the maximum theoretical amounts guaranteed under current agreements. Liabilities recognized represent the associated obligation of TEC under these agreements at Sept. 30, 2014. The obligations under these letters of credit include net accounts payable and net derivative liabilities.

Segment_Information_Tables

Segment Information (Tables)	9 Months Ended
Segment Information (Tables)	Sep. 30, 2014
Segment Reporting [Abstract]	'
Schedule of Segment Information	'
	TECO Energy is an electric and gas utility holding company with diversified activities. Segments are determined based on how management evaluates, measures and makes decisions with respect to the operations of the entity. The management of TECO Energy reports segments based on each subsidiary’s contribution of revenues, net income and total assets as required by the accounting guidance for disclosures about segments of an enterprise and related information. All significant intercompany transactions are eliminated in the Consolidated Condensed Financial Statements of TECO Energy, but are included in determining reportable segments.


	Segment Information (1)
	(millions)	Tampa			Peoples			New Mexico				TECO			Other &			TECO
	Three months ended Sep 30,	Electric			Gas			Gas Co. (2)				Coal (1)			Eliminations (2)			Energy
	2014
	Revenues - external	$	581.5		$	86.9		$	16.2			$	0		$	2.6		$	687.2
	Sales to affiliates		0.3			0			0				0			(0.3	)		0
	Total revenues		581.8			86.9			16.2				0			2.3			687.2
	Depreciation and amortization		61.8			13.6			2.8				0			0.4			78.6
	Total interest charges		23.8			3.5			1.1				0			14.5			42.9
	Provision (benefit) for income taxes		48.5			3			(0.5	)			0			(17.3	)		33.7
	Net income (loss) from continuing operations		79.7			4.8			(0.9	)			0			(10.6	)		73
	Income from discontinued operations, net (1)		0			0			0				(64.8	)		2.9			(61.9	)
	Net income (loss)	$	79.7		$	4.8		$	(0.9	)		$	(64.8	)	$	(7.7	)	$	11.1
	2013
	Revenues - external	$	556.2		$	83.1		$	0			$	0		$	2.8		$	642.1
	Sales to affiliates		0.2			0.3			0				0			(0.5	)		0
	Total revenues		556.4			83.4			0				0			2.3			642.1
	Depreciation and amortization		62.2			13.4			0				0			0.5			76.1
	Total interest charges		22.8			3.4			0				0			13.7			39.9
	Provision (benefit) for income taxes		42.7			3.4			0				0			(7.2	)		38.9
	Net income (loss) from continuing operations		68.7			5.4			0				0			(9.8	)		64.3
	Income from discontinued operations, net (1)		0			0			0				(1.4	)		(0.1	)		(1.5	)
	Net income (loss)	$	68.7		$	5.4		$	0			$	(1.4	)	$	(9.9	)	$	62.8


	(millions)	Tampa			Peoples			New Mexico				TECO			Other &			TECO
	Nine months ended Sep 30,	Electric			Gas			Gas Co. (2)				Coal (1)			Eliminations (2)			Energy
	2014
	Revenues - external	$	1,546.90		$	300		$	16.2			$	0		$	7.8		$	1,870.90
	Sales to affiliates		0.8			0.6			0				0			(1.4	)		0
	Total revenues		1,547.70			300.6			16.2				0			6.4			1,870.90
	Depreciation and amortization		185.6			40.3			2.8				0			1.3			230
	Total interest charges		69.1			10.3			1.1				0			42.7			123.2
	Provision (benefit) for income taxes		112.2			17			(0.5	)			0			(30.7	)		98
	Net income (loss) from continuing operations		187.1			26.9			(0.9	)			0			(34.1	)		179
	Income from discontinued operations, net (1)		0			0			0				(65.6	)		6.2			(59.4	)
	Net income (loss)	$	187.1		$	26.9		$	(0.9	)		$	(65.6	)	$	(27.9	)	$	119.6
	2013
	Revenues - external	$	1,476.60		$	306.3		$	0			$	0		$	10		$	1,792.90
	Sales to affiliates		0.7			0.8			0				0			(1.5	)		0
	Total revenues		1,477.30			307.1			0				0			8.5			1,792.90
	Depreciation and amortization		182			39.6			0				0			1.2			222.8
	Total interest charges		69.5			10.1			0				0			42			121.6
	Provision (benefit) for income taxes		94			17.1			0				0			(19.7	)		91.4
	Net income (loss) from continuing operations		151.1			27.1			0				0			(24.9	)		153.3
	Income from discontinued operations, net (1)		0			0			0				2.3			0.1			2.4
	Net income (loss)	$	151.1		$	27.1		$	0			$	2.3		$	(24.8	)	$	155.7
	At Sep 30, 2014
	Goodwill	$	0		$	0		$	401.8			$	0		$	0		$	401.8
	Assets held for sale, current		0			0			0				133.7			0			133.7
	Assets held for sale, non-current		0			0			0				78.6			0			78.6
	Total assets	$	6,485.50		$	1,034.10		$	1,171.40			$	261.8		$	(299.2	)	$	8,653.60
	At Dec 31, 2013
	Total assets	$	6,126.90		$	1,021.20		$	0			$	316.3		$	(16.4	)	$	7,448.00

	(1) All periods have been adjusted to reflect the reclassification of results from operations to discontinued operations for TECO Coal and certain charges at Parent that directly relate to TECO Coal. See Note 15.
	(2) NMGI is included in the Other & Eliminations segment.


	(millions)	Tampa			Peoples			Other &				Tampa Electric
Three months ended Sep 30,	Electric			Gas			Eliminations				Company
2014
Revenues - external	$	581.6		$	86.9		$	0			$	668.5
Sales to affiliates		0.2			0			(0.2	)			0
Total revenues		581.8			86.9			(0.2	)			668.5
Depreciation and amortization		61.8			13.6			0				75.4
Total interest charges		23.8			3.5			0				27.3
Provision for income taxes		48.5			3			0				51.5
Net income	$	79.7		$	4.8		$	0			$	84.5
2013
Revenues - external	$	556.3		$	83.1		$	0			$	639.4
Sales to affiliates		0.1			0.3			(0.4	)			0
Total revenues		556.4			83.4			(0.4	)			639.4
Depreciation and amortization		62.2			13.4			0				75.6
Total interest charges		22.8			3.4			0				26.2
Provision for income taxes		42.7			3.4			0				46.1
Net income	$	68.7		$	5.4		$	0			$	74.1
Nine months ended Sep 30,
2014
Revenues - external	$	1,547.30		$	300		$	0			$	1,847.30
Sales to affiliates		0.4			0.6			(1.0	)			0
Total revenues		1,547.70			300.6			(1.0	)			1,847.30
Depreciation and amortization		185.6			40.3			0				225.9
Total interest charges		69.1			10.3			0				79.4
Provision for income taxes		112.2			17			0				129.2
Net income	$	187.1		$	26.9		$	0			$	214
Total assets at Sept. 30, 2014	$	6,160.80		$	1,002.40		$	(8.9	)		$	7,154.30
2013
Revenues - external	$	1,477.00		$	306.3		$	0			$	1,783.30
Sales to affiliates		0.3			0.8			(1.1	)			0
Total revenues		1,477.30			307.1			(1.1	)			1,783.30
Depreciation and amortization		182			39.6			0				221.6
Total interest charges		69.5			10.1			0				79.6
Provision for income taxes		94			17.1			0				111.1
Net income	$	151.1		$	27.1		$	0			$	178.2
Total assets at Dec. 31, 2013	$	5,895.40		$	989.3		$	(8.9	)		$	6,875.80

Accounting_for_Derivative_Inst1

Accounting for Derivative Instruments and Hedging Activities (Tables)	9 Months Ended
	Sep. 30, 2014
Fair Values and Locations of Derivative Instruments Recorded on Balance Sheet	'
	The following table presents the derivatives that are designated as cash flow hedges at Sept. 30, 2014 and Dec. 31, 2013:

	Total Derivatives (1)
		Sep 30,				Dec 31,
	(millions)	2014				2013
	Current assets	$	0.2			$	9.7
	Long-term assets		0				0.3
	Total assets	$	0.2			$	10

	Current liabilities	$	4.1			$	0.1
	Long-term liabilities		1.6				0.2
	Total liabilities	$	5.7			$	0.3
	-1	Amounts presented above are on a gross basis, with asset and liability positions netted by counterparty in accordance with accounting standards for derivatives and hedging.
Gross Amounts of Derivatives and Their Related Offset Amounts	'
	The following table presents the gross amounts of derivatives and their related offset amounts as permitted by their respective master netting agreements at Sept. 30, 2014 and Dec. 31, 2013. There was no collateral posted with or received from any counterparties.

	Offsetting of Derivative Assets and Liabilities
	(millions)
		Gross Amounts of Recognized Assets (Liabilities)				Gross Amounts offset on the Balance Sheet				Net Amounts of Assets (Liabilities) Presented on the Balance Sheet
	30-Sep-14
	Description
	Derivative assets	$	1.4			$	(1.2	)		$	0.2
	Derivative liabilities	$	(6.9	)		$	1.2			$	(5.7	)

	31-Dec-13
	Description
	Derivative assets	$	10.5			$	(0.5	)		$	10
	Derivative liabilities	$	(0.8	)		$	0.5			$	(0.3	)

Effect of Hedging Instruments on OCI and Income	'
	The following table presents the effect of hedging instruments on OCI and income for the three and nine months ended Sept. 30. All diesel fuel derivatives are expected to be settled prior to the closing on the sale of TECO Coal.

	Effect of Hedging Instruments on OCI and Income
	For the three months ended Sep 30:	Amount of				Location of		Amount of
		Gain/(Loss) on				Gain/(Loss)		Gain/(Loss)
		Derivatives				Reclassified		Reclassified
		Recognized in				From AOCI		From AOCI
	(millions)	OCI				Into Income		Into Income
	Derivatives in Cash Flow Hedging	Effective Portion (1)						Effective Portion (1)
	Relationships	Effective Portion (1)						Effective Portion (1)
	2014
	Interest rate contracts	$	0			Interest expense		$	(0.3	)
	Commodity contracts:
	Diesel fuel derivatives		(0.2	)		Loss from discontinued operations			0
	Total	$	(0.2	)				$	(0.3	)
	2013
	Interest rate contracts	$	0			Interest expense		$	(0.2	)
	Commodity contracts:
	Diesel fuel derivatives		0.7			Loss from discontinued operations			0.1
	Total	$	0.7					$	(0.1	)



	For the nine months ended Sep 30:	Amount of				Location of		Amount of
		Gain/(Loss) on				Gain/(Loss)		Gain/(Loss)
		Derivatives				Reclassified		Reclassified
		Recognized in				From AOCI		From AOCI
	(millions)	OCI				Into Income		Into Income
	Derivatives in Cash Flow Hedging	Effective Portion (1)						Effective Portion (1)
	Relationships	Effective Portion (1)						Effective Portion (1)
	2014
	Interest rate contracts	$	0			Interest expense		$	(0.5	)
	Commodity contracts:
	Diesel fuel derivatives		(0.2	)		Loss from discontinued operations			(0.1	)
	Total	$	(0.2	)				$	(0.6	)
	2013
	Interest rate contracts	$	0			Interest expense		$	(0.7	)
	Commodity contracts:
	Diesel fuel derivatives		0.4			Loss from discontinued operations			0
	Total	$	0.4					$	(0.7	)
	(1) Changes in OCI and AOCI are reported in after-tax dollars.
	For derivative instruments that meet cash flow hedge criteria, the effective portion of the gain or loss on the derivative is reported as a component of OCI and reclassified into earnings in the same period or period during which the hedged transaction affects earnings. Gains and losses on the derivatives representing either hedge ineffectiveness or hedge components excluded from the assessment of effectiveness are recognized in current earnings. For the three and nine months ended Sept. 30, 2014 and 2013, all hedges were effective.
	The following table presents the derivative activity for instruments classified as qualifying cash flow hedges for the nine months ended Sept. 30. All diesel fuel derivatives are expected to be settled prior to the closing on the sale of TECO Coal.

	Qualifying Cash Flow Hedges
						Amount of				Amount of
		Fair Value				Gain/(Loss)				Gain/(Loss)
		Asset/				Recognized				Reclassified From
	(millions)	(Liability)				in OCI (1)				AOCI Into Income
	2014
	Interest rate swaps	$	0			$	0			$	(0.5	)
	Diesel fuel derivatives		0				(0.2	)			(0.1	)
	Total	$	0			$	(0.2	)		$	(0.6	)
	2013
	Interest rate swaps	$	0			$	0			$	(0.7	)
	Diesel fuel derivatives		0.1				0.4				0
	Total	$	0.1			$	0.4			$	(0.7	)
	-1	Changes in OCI and AOCI are reported in after-tax dollars.
Derivative Volumes Expected to Settle	'
	The maximum length of time over which the company is hedging its exposure to the variability in future cash flows extends to Dec. 31, 2014 for financial diesel fuel contracts and Dec. 31, 2016 for financial natural gas contracts. The following table presents by commodity type the company’s derivative volumes that, as of Sept. 30, 2014, are expected to settle during the 2014, 2015 and 2016 fiscal years:

	Derivative Volumes	Diesel Fuel Contracts								Natural Gas Contracts
	(millions)	(Gallons)								(MMBTUs)
	Year	Physical				Financial				Physical			Financial
	2014		0				0.5				0			11.6
	2015		0				0				0			32.2
	2016		0				0				0			7.6
	Total		0				0.5				0			51.4

Tampa Electric Company [Member]	'
Fair Values and Locations of Derivative Instruments Recorded on Balance Sheet	'
	The following table presents the derivative hedges of natural gas contracts at Sept. 30, 2014 and Dec. 31, 2013 to limit the exposure to changes in the market price for natural gas used to produce energy and natural gas purchased for resale to customers:

	Natural Gas Derivatives
		Sept. 30,				Dec. 31,
	(millions)	2014				2013
	Current assets	$	0.1			$	9.5
	Long-term assets		0				0.3
	Total assets	$	0.1			$	9.8
	Current liabilities (1)	$	4			$	0
	Long-term liabilities		1.6				0.2
	Total liabilities	$	5.6			$	0.2
	-1	Amounts presented above are on a gross basis, with asset and liability positions netted by counterparty in accordance with accounting standards for derivatives and hedging.
Gross Amounts of Derivatives and Their Related Offset Amounts	'
	The following table presents the gross amounts of derivatives and their related offset amounts as permitted by their respective master netting agreements at Sept. 30, 2014 and Dec. 31, 2013. There was no collateral posted with or received from any counterparties:

	Offsetting of Derivative Assets and Liabilities

	(millions)	Gross Amounts of Recognized Assets (Liabilities)				Gross Amounts offset on the Balance Sheet				Net Amounts of Assets (Liabilities) Presented on the Balance Sheet
	30-Sep-14
	Description
	Derivative assets	$	1.4			$	(1.3	)		$	0.1
	Derivative liabilities	$	(6.9	)		$	1.3			$	(5.6	)

	31-Dec-13
	Description
	Derivative assets	$	10.3			$	(0.5	)		$	9.8
	Derivative liabilities	$	(0.7	)		$	0.5			$	(0.2	)

Effect of Hedging Instruments on OCI and Income	'


	The following table presents the effect of hedging instruments on OCI and income for the three months and nine months ended Sept. 30:

	(millions)	Location of Gain/(Loss) Reclassified From AOCI Into Income		Amount of Gain/(Loss) Reclassified From AOCI Into Income
	Derivatives in Cash Flow Hedging Relationships	Effective Portion (1)		Three months				Nine months
	Derivatives in Cash Flow Hedging Relationships	Effective Portion (1)		ended Sep 30:				ended Sep 30:
	2014
	Interest rate contracts:	Interest expense		$	(0.3	)		$	(0.5	)
	Total			$	(0.3	)		$	(0.5	)
	2013
	Interest rate contracts:	Interest expense		$	(0.2	)		$	(0.7	)
	Total			$	(0.2	)		$	(0.7	)
	-1	Changes in OCI and AOCI are reported in after-tax dollars.
Derivative Volumes Expected to Settle	'
	The maximum length of time over which TEC is hedging its exposure to the variability in future cash flows extends to Dec. 31, 2016 for the financial natural gas contracts. The following table presents by commodity type TEC’s derivative volumes that, as of Sept. 30, 2014, are expected to settle during the 2014, 2015 and 2016 fiscal years:

		Natural Gas Contracts
	(millions)	(MMBTUs)
	Year	Physical				Financial
	2014		0				11.6
	2015		0				32.2
	2016		0				7.6
	Total		0				51.4

Energy Related Derivatives [Member]	'
Fair Values and Locations of Derivative Instruments Recorded on Balance Sheet	'
	The following tables present the effect of energy related derivatives on the fuel recovery clause mechanism in the Consolidated Condensed Balance Sheets as of Sept. 30, 2014 and Dec. 31, 2013:

	Energy Related Derivatives
		Asset Derivatives						Liability Derivatives
	(millions)	Balance Sheet		Fair				Balance Sheet		Fair
	30-Sep-14	Location (1)		Value				Location (1)		Value
	Commodity Contracts:

	Natural gas derivatives:
	Current	Regulatory liabilities		$	0.1			Regulatory assets		$	4
	Long-term	Regulatory liabilities			0			Regulatory assets			1.6
	Total			$	0.1					$	5.6

	(millions)	Balance Sheet		Fair				Balance Sheet		Fair
	31-Dec-13	Location (1)		Value				Location (1)		Value
	Commodity Contracts:

	Natural gas derivatives:
	Current	Regulatory liabilities		$	9.5			Regulatory assets		$	0
	Long-term	Regulatory liabilities			0.3			Regulatory assets			0.2
	Total			$	9.8					$	0.2

Energy Related Derivatives [Member] \| Tampa Electric Company [Member]	'
Fair Values and Locations of Derivative Instruments Recorded on Balance Sheet	'
	The following table presents the effect of energy related derivatives on the fuel recovery clause mechanism in the Consolidated Condensed Balance Sheets as of Sept. 30, 2014 and Dec. 31, 2013:

	Energy Related Derivatives
		Asset Derivatives						Liability Derivatives
	(millions)	Balance Sheet		Fair				Balance Sheet		Fair
	30-Sep-14	Location (1)		Value				Location (1)		Value
	Commodity Contracts:

	Natural gas derivatives:
	Current	Regulatory liabilities		$	0.1			Regulatory assets		$	4
	Long-term	Regulatory liabilities			0			Regulatory assets			1.6
	Total			$	0.1					$	5.6

	(millions)	Balance Sheet		Fair				Balance Sheet		Fair
	31-Dec-13	Location (1)		Value				Location (1)		Value
	Commodity Contracts:

	Natural gas derivatives:
	Current	Regulatory liabilities		$	9.5			Regulatory assets		$	0
	Long-term	Regulatory liabilities			0.3			Regulatory assets			0.2
	Total			$	9.8					$	0.2
	—	Natural gas derivatives are deferred in accordance with accounting standards for regulated operations and all increases and decreases in the cost of natural gas supply are passed on to customers with the fuel recovery clause mechanism. As gains and losses are realized in future periods, they will be recorded as fuel costs in the Consolidated Condensed Statements of Income.
Derivatives Designated as Hedging Instruments [Member]	'
Fair Values and Locations of Derivative Instruments Recorded on Balance Sheet	'
	The following tables present the fair values and locations of derivative instruments recorded on the balance sheet at Sept. 30, 2014 and Dec. 31, 2013. All diesel fuel derivatives are expected to be settled prior to the closing on the sale of TECO Coal.


	Derivatives Designated as Hedging Instruments
		Asset Derivatives						Liability Derivatives
	(millions)	Balance Sheet		Fair				Balance Sheet		Fair
	30-Sep-14	Location		Value				Location		Value
	Commodity Contracts:

	Diesel fuel derivatives:
	Current	Derivative assets		$	0.1			Derivative liabilities		$	0.1
	Long-term	Derivative assets			0			Derivative liabilities			0

	Natural gas derivatives:
	Current	Derivative assets			0.1			Derivative liabilities			4
	Long-term	Derivative assets			0			Derivative liabilities			1.6
	Total derivatives designated as hedging instruments			$	0.2					$	5.7

		Asset Derivatives						Liability Derivatives
	(millions)	Balance Sheet		Fair				Balance Sheet		Fair
	31-Dec-13	Location		Value				Location		Value
	Commodity Contracts:

	Diesel fuel derivatives:
	Current	Derivative assets		$	0.2			Derivative liabilities		$	0.1
	Long-term	Derivative assets			0			Derivative liabilities			0

	Natural gas derivatives:
	Current	Derivative assets			9.5			Derivative liabilities			0
	Long-term	Derivative assets			0.3			Derivative liabilities			0.2
	Total derivatives designated as hedging instruments			$	10					$	0.3

Diesel Fuel Derivatives [Member]	'
Fair Values and Locations of Derivative Instruments Recorded on Balance Sheet	'
	The following table presents the derivative hedges of diesel fuel contracts at Sept. 30, 2014 and Dec. 31, 2013 to limit the exposure to changes in the market price for diesel fuel used in the production of coal. All diesel fuel derivatives are expected to be settled prior to the closing of the sale of TECO Coal.

	Diesel Fuel Derivatives
			Sep 30,				Dec 31,
	(millions)		2014				2013
	Current assets		$	0.1			$	0.2
	Long-term assets			0				0
	Total assets		$	0.1			$	0.2

	Current liabilities		$	0.1			$	0.1
	Long-term liabilities			0				0
	Total liabilities		$	0.1			$	0.1

Natural Gas Derivatives [Member]	'
Fair Values and Locations of Derivative Instruments Recorded on Balance Sheet	'
	The following table presents the derivative hedges of natural gas contracts at Sept. 30, 2014 and Dec. 31, 2013 to limit the exposure to changes in market price for natural gas used to produce energy and natural gas purchased for resale to customers:

	Natural Gas Derivatives
			Sep 30,				Dec 31,
	(millions)		2014				2013
	Current assets		$	0.1			$	9.5
	Long-term assets			0				0.3
	Total assets		$	0.1			$	9.8

	Current liabilities		$	4			$	0
	Long-term liabilities			1.6				0.2
	Total liabilities		$	5.6			$	0.2

Fair_Value_Measurements_Tables

Fair Value Measurements (Tables)	9 Months Ended
Fair Value Measurements (Tables)	Sep. 30, 2014
Schedule of Recurring Fair Value Measurements	'
	For natural gas and diesel fuel swaps, the market approach was used in determining fair value.

	Recurring Fair Value Measures
		At fair value as of Sep 30, 2014
	(millions)	Level 1		Level 2		Level 3		Total
	Assets
	Natural gas swaps	$	0	$	0.1	$	0	$	0.1
	Diesel fuel swaps		0		0.1		0		0.1
	Total	$	0	$	0.2	$	0	$	0.2

	Liabilities
	Natural gas swaps	$	0	$	5.6	$	0	$	5.6
	Diesel fuel swaps		0		0.1		0		0.1
	Total	$	0	$	5.7	$	0	$	5.7


		At fair value as of Dec 31, 2013
	(millions)	Level 1		Level 2		Level 3		Total
	Assets
	Natural gas swaps	$	0	$	9.8	$	0	$	9.8
	Diesel fuel swaps		0		0.2		0		0.2
	Total	$	0	$	10	$	0	$	10

	Liabilities
	Natural gas swaps	$	0	$	0.2	$	0	$	0.2
	Diesel fuel swaps		0		0.1		0		0.1
	Total	$	0	$	0.3	$	0	$	0.3

Tampa Electric Company [Member]	'
Schedule of Recurring Fair Value Measurements	'
	For all assets and liabilities presented below, the market approach was used in determining fair value.
	Recurring Derivative Fair Value Measures
		At fair value as of Sep 30, 2014
	(millions)	Level 1		Level 2		Level 3		Total
	Assets
	Natural gas swaps	$	0	$	0.1	$	0	$	0.1
	Total	$	0	$	0.1	$	0	$	0.1

	Liabilities
	Natural gas swaps	$	0	$	5.6	$	0	$	5.6
	Total	$	0	$	5.6	$	0	$	5.6

		At fair value as of Dec 31, 2013
	(millions)	Level 1		Level 2		Level 3		Total
	Assets
	Natural gas swaps	$	0	$	9.8	$	0	$	9.8
	Total	$	0	$	9.8	$	0	$	9.8

	Liabilities
	Natural gas swaps	$	0	$	0.2	$	0	$	0.2
	Total	$	0	$	0.2	$	0	$	0.2

Discontinued_Operations_Assets1

Discontinued Operations, Assets Held for Sale and Asset Impairments Sale (Tables)	9 Months Ended
	Sep. 30, 2014
TECO Coal [Member]	'
Components of Discontinued Operations	'
	The following table provides a summary of the carrying amounts of the significant assets and liabilities reported in the combined current and non-current “Assets held for sale” and “Liabilities associated with assets held for sale” line items:

	Assets held for sale
	(millions)	30-Sep-14
	Current assets	$	133.7
	Property, plant and equipment, net and other long-term assets		78.6
	Total assets held for sale	$	212.3

	Liabilities associated with assets held for sale
	(millions)
	Current liabilities	$	41.1
	Long-term liabilities		64.4
	Total liabilities associated with assets held for sale	$	105.5

TECO Coal and TECO Guatemala [Member]	'
Components of Discontinued Operations	'
	The following table provides selected components of discontinued operations related to the sales of TECO Coal and TECO Guatemala:

	Components of income from discontinued operations	Three months ended						Nine months ended
		Sep 30,						Sep 30,
	(millions)	2014			2013			2014			2013
	Revenues	$	101.6		$	123.7		$	328.3		$	370
	(Loss) Income from operations (1)		(0.4	)		(2.9	)		0.8			0
	(Loss) on impairment		(98.4	)		0			(98.4	)		0
	(Loss) Income from discontinued operations (2)		(98.8	)		(2.9	)		(97.6	)		0
	(Benefit) Provision for income taxes (3)		(36.9	)		(1.4	)		(38.2	)		(2.4	)
	(Loss) Income from discontinued operations, net	$	(61.9	)	$	(1.5	)	$	(59.4	)	$	2.4

	-1	TECO Guatemala related amounts included above are $(0.2) million and $5.0 million during the three months ended Sept. 30, 2013 and nine months ended Sept. 30, 2014, respectively. Other periods have no reportable amount.
	-2	TECO Guatemala related amounts included above are $(0.2) million and $5.0 million during the three months ended Sept. 30, 2013 and nine months ended Sept. 30, 2014, respectively. Other periods have no reportable amount.
	-3	TECO Guatemala related amounts included above are $(0.1) million and $1.9 million during the three months ended Sept. 30, 2013 and nine months ended Sept. 30, 2014, respectively. Other periods have no reportable amount.

Acquisition_of_New_Mexico_Gas_1

Acquisition of New Mexico Gas Intermediate (Tables)	9 Months Ended
Acquisition of New Mexico Gas Intermediate (Tables)	Sep. 30, 2014
Pro Forma Financial Information	'
	Pro Forma Impact of Acquisition	Three months ended Sep 30,					Nine months ended Sep 30,
	(millions, except per share amounts)	2014			2013		2014			2013
	Revenues	$	720		$	684.5	$	2,111.00		$	2,024.10
	Net income from continuing operations	$	70.8		$	64.9	$	199.3		$	171.4
	Basic and Diluted EPS from continuing operations	$	0.31		$	0.28	$	0.86		$	0.74

Schedule of Goodwill	'
	Goodwill
	(millions)	NMGC			Total
	Balance as of Jul 1, 2014	$	0		$	0
	Goodwill acquired in business acquisition		401.8		$	401.8
	Balance as of Sep 30, 2014	$	401.8		$	401.8

Intangible Assets and Liabilities Acquired Through Acquisition Included in Consolidated Balance Sheets, Along with Future Estimated Amortization	'
	The company’s intangible assets and liabilities acquired through the acquisition of NMGI included in its Consolidated Condensed Balance Sheets, along with the future estimated amortization, were as follows as of Sept. 30, 2014:

	Description	Weighted average amortization (years) (a)			Gross		Accumulated amortization			Net		2014		2015		2016		2017		2018		2019 and beyond
	Rights-of-way		17		$	27.2	$	(0.1	)	$	27.1	$	0.3	$	1.4	$	1.4	$	1.4	$	1.4	$	21.2

	—	Weighted average amortization period was calculated as of the date of acquisition.
Pretax Transaction and Integration Charges Recognized Upon Closing of Acquisition and Included Consolidated Statements of Operations	'
	The following after-tax transaction and integration charges were recognized in connection with the acquisition and are included in the TECO Energy Consolidated Statements of Operations for the nine months ended Sept. 30, 2014.

	Transaction and Integration Costs	Total
	(millions)
	Legal and other consultants	$	7.2
	Bridge loan costs		2.9
	Employee expenses		0.2
	Severance and relocation costs		1.7
	Other costs and tax benefit		(4.5	)
	Total accounting charges	$	7.5

NMGI [Member]	'
Consideration in Acquisition	'
	The total consideration in the acquisition was as follows:

	Consideration Transferred
	(millions)
	Cash	$	530.1
	Long-term debt assumed or settled, including accrued interest and fees		419.9
	Total consideration transferred, excluding cash and working capital adjustments	$	950

NMGI and NMGC [Member]	'
Preliminary Purchase Price Allocation	'
	The preliminary purchase price allocation of the acquisition of NMGI and NMGC is as follows:

	Preliminary Purchase Price Allocation
	(millions)
	Current assets (a)	$	48.7
	Property, plant and equipment		618.9
	OPEB regulatory asset		6.4
	Debt-related regulatory asset		23.9
	Goodwill		401.8
	Deferred tax assets		52.8
	Other assets		30.2
	Total assets	$	1,182.70
	Current liabilities	$	(35.0	)
	Long-term debt fair value adjustment and interest assumed		(22.7	)
	Cost of removal regulatory liability		(100.6	)
	Deferred tax liabilities		(60.8	)
	OPEB liability		(9.8	)
	Deferred credits and other liabilities		(3.8	)
	Total liabilities	$	(232.7	)
	Total purchase price allocation, excluding cash and working capital adjustments	$	950

	-1	Includes accounts receivables with fair value of $18.9 million, gross contract value of $19.6 million, and $0.7 million of contractual receivables not expected to be collected.

Summary_of_Significant_Account2

Summary of Significant Accounting Policies - Additional Information (Detail) (USD $)

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

In Millions, unless otherwise specified

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Tampa Electric Company [Member]

Unbilled Revenues [Member]

Tampa Electric Company [Member]

Summary Of Significant Accounting Policies [Line Items]

Unbilled revenues

$61

$46.70

$53.30

$46.70

Franchise fees and gross receipts taxes

$31.70

$29.70

$86.70

$81.80

$31.70

$29.70

$86.70

$81.80

Regulatory_Additional_Informat

Regulatory - Additional Information (Detail) (USD $)	0 Months Ended	1 Months Ended					9 Months Ended
	Feb. 01, 2012	Mar. 31, 2011	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Dec. 31, 2013	Sep. 30, 2014	Dec. 31, 2013
					Tampa Electric Company [Member]	Tampa Electric Company [Member]	Tampa Electric Company [Member]	Tampa Electric Company [Member]
							Transmission and Delivery Storm Reserve [Member]	Transmission and Delivery Storm Reserve [Member]
Application to increase base rate on normalized annual basis	'	$34,500,000	'	'	'	'	'	'
Increased Base Rate on Normalized Annual Basis	21,500,000	'	'	'	'	'	'	'
Monthly residential customer access fee increase proposal	9.59	'	'	'	'	'	'	'
Monthly residential customer access fee increased	11.5	'	'	'	'	'	'	'
Annual accrual storm damage reserve	'	'	'	'	8,000,000	'	'	'
Storm damage reserve	'	'	$793,000,000	$717,200,000	$688,000,000	$717,200,000	$56,100,000	$56,100,000
Storm damage cost recovery period	'	'	'	'	'	'	'12 months	'

Regulatory_Schedule_of_Regulat

Regulatory - Schedule of Regulatory Assets and Regulatory Liabilities (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Regulatory assets:	'	'
Regulatory assets	$366.50	$327.40
Less: Current portion	24.3	34.3
Long-term regulatory assets	342.2	293.1
Regulatory liabilities:	'	'
Regulatory liabilities	793	717.2
Less: Current portion	65.8	85.8
Long-term regulatory liabilities	727.2	631.4
Tampa Electric Company [Member]	'	'
Regulatory assets:	'	'
Regulatory assets	334.6	327.4
Less: Current portion	22.9	34.3
Long-term regulatory assets	311.7	293.1
Regulatory liabilities:	'	'
Regulatory liabilities	688	717.2
Less: Current portion	64.5	85.8
Long-term regulatory liabilities	623.5	631.4
Regulatory Tax Asset [Member]	'	'
Regulatory assets:	'	'
Regulatory assets	69.1	67.4
Regulatory Tax Asset [Member] \| Tampa Electric Company [Member]	'	'
Regulatory assets:	'	'
Regulatory assets	68.6	67.4
Cost-Recovery Clauses [Member]	'	'
Regulatory assets:	'	'
Regulatory assets	9.3	6.1
Cost-Recovery Clauses [Member] \| Tampa Electric Company [Member]	'	'
Regulatory assets:	'	'
Regulatory assets	8	6.1
Postretirement Benefit Asset [Member]	'	'
Regulatory assets:	'	'
Regulatory assets	194.1	182.7
Postretirement Benefit Asset [Member] \| Tampa Electric Company [Member]	'	'
Regulatory assets:	'	'
Regulatory assets	187.8	182.7
Deferred Bond Refinancing Costs [Member]	'	'
Regulatory assets:	'	'
Regulatory assets	9.2	8
Deferred Bond Refinancing Costs [Member] \| Tampa Electric Company [Member]	'	'
Regulatory assets:	'	'
Regulatory assets	7.4	8
Deferred Bond Refinancing Costs [Member]	'	'
Regulatory assets:	'	'
Regulatory assets	21.7	0
Environmental Remediation [Member]	'	'
Regulatory assets:	'	'
Regulatory assets	52.3	51.4
Environmental Remediation [Member] \| Tampa Electric Company [Member]	'	'
Regulatory assets:	'	'
Regulatory assets	52.3	51.4
Competitive Rate Adjustment [Member]	'	'
Regulatory assets:	'	'
Regulatory assets	2.6	4.1
Competitive Rate Adjustment [Member] \| Tampa Electric Company [Member]	'	'
Regulatory assets:	'	'
Regulatory assets	2.6	4.1
Other [Member]	'	'
Regulatory assets:	'	'
Regulatory assets	8.2	7.7
Other [Member] \| Tampa Electric Company [Member]	'	'
Regulatory assets:	'	'
Regulatory assets	7.9	7.7
Total Other Regulatory Assets [Member]	'	'
Regulatory assets:	'	'
Regulatory assets	297.4	260
Total Other Regulatory Assets [Member] \| Tampa Electric Company [Member]	'	'
Regulatory assets:	'	'
Regulatory assets	266	260
Regulatory Tax Liability [Member]	'	'
Regulatory liabilities:	'	'
Regulatory liabilities	6.7	9.8
Regulatory Tax Liability [Member] \| Tampa Electric Company [Member]	'	'
Regulatory liabilities:	'	'
Regulatory liabilities	5.3	9.8
Cost-Recovery Clauses [Member]	'	'
Regulatory liabilities:	'	'
Regulatory liabilities	34.6	54.5
Cost-Recovery Clauses [Member] \| Tampa Electric Company [Member]	'	'
Regulatory liabilities:	'	'
Regulatory liabilities	33.1	54.5
Transmission and Delivery Storm Reserve [Member]	'	'
Regulatory liabilities:	'	'
Regulatory liabilities	56.1	56.1
Transmission and Delivery Storm Reserve [Member] \| Tampa Electric Company [Member]	'	'
Regulatory liabilities:	'	'
Regulatory liabilities	56.1	56.1
Deferred Gain on Property Sales [Member]	'	'
Regulatory liabilities:	'	'
Regulatory liabilities	1.1	2
Deferred Gain on Property Sales [Member] \| Tampa Electric Company [Member]	'	'
Regulatory liabilities:	'	'
Regulatory liabilities	1.1	2
Accumulated Reserve - Cost of Removal [Member]	'	'
Regulatory liabilities:	'	'
Regulatory liabilities	693.6	594
Accumulated Reserve - Cost of Removal [Member] \| Tampa Electric Company [Member]	'	'
Regulatory liabilities:	'	'
Regulatory liabilities	591.5	594
Other [Member]	'	'
Regulatory liabilities:	'	'
Regulatory liabilities	0.9	0.8
Other [Member] \| Tampa Electric Company [Member]	'	'
Regulatory liabilities:	'	'
Regulatory liabilities	0.9	0.8
Total Other Regulatory Liabilities [Member]	'	'
Regulatory liabilities:	'	'
Regulatory liabilities	786.3	707.4
Total Other Regulatory Liabilities [Member] \| Tampa Electric Company [Member]	'	'
Regulatory liabilities:	'	'
Regulatory liabilities	$682.70	$707.40

Regulatory_Schedule_of_Regulat1

Regulatory - Schedule of Regulatory Assets and Regulatory Liabilities (Parenthetical) (Detail)	9 Months Ended
	Sep. 30, 2014
Schedule Of Regulatory Assets And Liabilities [Line Items]	'
Amortization period	'5-year
Tampa Electric Company [Member]	'
Schedule Of Regulatory Assets And Liabilities [Line Items]	'
Amortization period	'5-year

Regulatory_Regulatory_Assets_a

Regulatory - Regulatory Assets and Related Recovery Periods (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Regulatory Asset [Line Items]	'	'
Regulatory assets	$366.50	$327.40
Tampa Electric Company [Member]	'	'
Regulatory Asset [Line Items]	'	'
Regulatory assets	334.6	327.4
Components of Rate Base [Member]	'	'
Regulatory Asset [Line Items]	'	'
Regulatory assets	199.3	185.6
Components of Rate Base [Member] \| Tampa Electric Company [Member]	'	'
Regulatory Asset [Line Items]	'	'
Regulatory assets	190.9	185.6
Clause Recoverable [Member]	'	'
Regulatory Asset [Line Items]	'	'
Regulatory assets	11.9	10.2
Clause Recoverable [Member] \| Tampa Electric Company [Member]	'	'
Regulatory Asset [Line Items]	'	'
Regulatory assets	10.6	10.2
Regulatory Tax Asset [Member]	'	'
Regulatory Asset [Line Items]	'	'
Regulatory assets	69.1	67.4
Regulatory Tax Asset [Member] \| Tampa Electric Company [Member]	'	'
Regulatory Asset [Line Items]	'	'
Regulatory assets	68.6	67.4
Capital Structure and Other [Member]	'	'
Regulatory Asset [Line Items]	'	'
Regulatory assets	86.2	64.2
Capital Structure and Other [Member] \| Tampa Electric Company [Member]	'	'
Regulatory Asset [Line Items]	'	'
Regulatory assets	$64.50	$64.20

Income_Taxes_Additional_Inform

Income Taxes - Additional Information (Detail)	9 Months Ended
Income Taxes - Additional Information (Detail)	Sep. 30, 2014	Sep. 30, 2013
Income Taxes [Line Items]	'	'
Income tax examination period	'1 year	'
Effective tax rate	35.38%	37.35%
Tampa Electric Company [Member]	'	'
Income Taxes [Line Items]	'	'
Statutes of limitations	'3 years	'
Income tax examination period	'1 year	'
Minimum [Member]	'	'
Income Taxes [Line Items]	'	'
Statutes of limitations	'3 years	'
Maximum [Member]	'	'
Income Taxes [Line Items]	'	'
Statutes of limitations	'4 years	'

Employee_Postretirement_Benefi2

Employee Postretirement Benefits - Schedule of Net Periodic Benefit Cost (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Pension Benefits [Member]	'	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'	'
Service cost	$4.60	$4.50	$12.90	$13.60
Interest cost on projected benefit obligations	8	7.3	24.4	21.7
Expected return on assets	-10.5	-9.6	-31.2	-28.8
Amortization of:	'	'	'	'
Prior service (benefit) cost	-0.1	-0.1	-0.3	-0.3
Actuarial loss	3.3	5.1	10	15.4
Regulatory asset	0	0	0	0
Settlement cost	0	1	0	1
Net pension expense recognized in the TECO Energy Consolidated Condensed Statements of Income	5.3	8.2	15.8	22.6
Other Postretirement Benefits [Member]	'	'	'	'
Defined Benefit Plan Disclosure [Line Items]	'	'	'	'
Service cost	0.6	0.7	1.8	1.9
Interest cost on projected benefit obligations	2.7	2.3	7.9	7
Expected return on assets	-0.1	0	-0.1	0
Amortization of:	'	'	'	'
Prior service (benefit) cost	0	-0.1	-0.1	-0.3
Actuarial loss	0	0.2	0.1	0.7
Regulatory asset	0.1	0	0.1	0
Settlement cost	0	0	0	0
Net pension expense recognized in the TECO Energy Consolidated Condensed Statements of Income	$3.30	$3.10	$9.70	$9.30

Employee_Postretirement_Benefi3

Employee Postretirement Benefits - Additional Information (Detail) (USD $)

3 Months Ended

9 Months Ended

0 Months Ended

3 Months Ended

9 Months Ended

0 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

0 Months Ended

3 Months Ended

9 Months Ended

In Millions, unless otherwise specified

Sep. 30, 2014

Dec. 31, 2013

Sep. 02, 2014

Sep. 30, 2014

Sep. 02, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 02, 2014

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

TECO Coal [Member]

Tampa Electric Company [Member]

Pension Benefits [Member]

ShortTerm_Debt_Credit_Faciliti

Short-Term Debt - Credit Facilities (Detail) (USD $)

Sep. 30, 2014

Dec. 31, 2013

Dec. 17, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Feb. 14, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

In Millions, unless otherwise specified

Tampa Electric Company [Member]

TECO Energy [Member]

New Mexico Gas Company [Member]

5-year Facility [Member]

1-year Accounts Receivable Facility [Member]

5-year Facility [Member]

Line Of Credit Facility [Line Items]

Credit Facilities

$900

$675

$40

$475

$325

$150

$300

$200

$125

Borrowings Outstanding

Letters of Credit Outstanding

$2.40

$0.70

$1.70

ShortTerm_Debt_Credit_Faciliti1

Short-Term Debt - Credit Facilities (Parenthetical) (Detail)	9 Months Ended	12 Months Ended
	Sep. 30, 2014	Dec. 31, 2013
Line Of Credit Facility [Line Items]	'	'
Credit facility maturity date	17-Dec-18	17-Dec-18
Tampa Electric Company [Member]	'	'
Line Of Credit Facility [Line Items]	'	'
Credit facility maturity date	17-Dec-18	17-Dec-18

ShortTerm_Debt_Additional_Info

Short-Term Debt - Additional Information (Detail) (USD $)

9 Months Ended

12 Months Ended

9 Months Ended

12 Months Ended

9 Months Ended

0 Months Ended

9 Months Ended

0 Months Ended

9 Months Ended

In Millions, unless otherwise specified

Sep. 30, 2014

Dec. 31, 2013

Dec. 17, 2013

Jun. 24, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

Feb. 14, 2014

Dec. 31, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 02, 2014

Sep. 30, 2014

Dec. 17, 2013

Sep. 30, 2014

Dec. 31, 2013

Sep. 30, 2014

NMGC Credit Agreement [Member]

Tampa Electric Company [Member]

New Mexico Gas Company [Member]

TECO Finance [Member]

Minimum [Member]

Maximum [Member]

1-year Accounts Receivable Facility [Member]

Amended Credit Agreement [Member]

NMGC Credit Agreement [Member]

Amended Credit Agreement [Member]

Tampa Electric Company [Member]

Letter of Credit

Line Of Credit Facility [Line Items]

Commitment fees, percentage

0.70%

0.13%

0.30%

Weighted-average interest rate

0.56%

1.37%

0.56%

1.37%

0.56%

Amended credit facility

$900

$675

$40

$125

$475

$150

$325

$125

$200

$300

Debt instrument maturity date

'2015-02-13

Basis spread on federal funds rate

0.50%

Credit Facility Amendment Date

14-Feb-14

Line Of Credit Facility Maximum Borrowing Capacity

900

675

125

475

150

325

125

200

300

Credit facility maturity date

17-Dec-18

Interest rate description

'as an alternative to the above interest rate, allows NMGC to borrow funds at an interest rate equal to a margin plus the higher of JPMorgan Chase Bankbs prime rate, the federal funds rate plus 50 basis points, or the London interbank deposit rate plus 1.00%;

Increase of credit facility

Senior unsecured bridge credit

1,075

Outstanding borrowings

LongTerm_Debt_Additional_Infor

Long-Term Debt - Additional Information (Detail) (USD $)

Sep. 30, 2014

Dec. 31, 2013

Jul. 16, 2014

Feb. 08, 2011

Sep. 30, 2014

Dec. 31, 2013

15-May-14

Sep. 30, 2014

Sep. 02, 2014

In Millions, unless otherwise specified

New Mexico Gas Company 4.87 % Notes due 2021 [Member]

Tampa Electric Company [Member]

New Mexico Gas Intermediate [Member]

New Mexico Gas Company [Member]

4.35% Notes [Member]

Series A Senior Unsecured Notes 2.71% Notes due 2019 [Member]

Series B Senior Unsecured 3.64 % Notes due 2024 [Member]

Senior Unsecured 3.54 % Notes due 2026 [Member]

New Mexico Gas Company 4.87 % Notes due 2021 [Member]

Debt Instrument [Line Items]

Long-term debt, carrying amount

$3,629.30

$2,921.10

$2,097.10

$1,880.80

Estimated fair value

3,949.60

3,184.10

2,330.30

2,042

Aggregate principal amount issued

200

300

150

Interest at the initial term rate per annum

4.35%

2.71%

3.64%

3.54%

4.87%

Debt instrument principal amount market price percentage

99.93%

100.00%

Proceeds from notes net of issuance

$296.60

$49.30

$149.10

$69.30

Redeemable principal amount percentage

100.00%

Debt instrument, offering date

16-Jul-14

8-Feb-11

15-May-14

2-Sep-14

Debt instrument, start date of redemption

15-Nov-43

30-Jul-19

30-Jul-24

30-Jul-26

Libor interest rate

'15

'50

Debt instrument, maturity year

'2044

'2019

'2024

'2026

'2021

Redeemable principal amount percentage

100.00%

Issuance of notes, maturity year

8-Feb-21

1-Jan-44

Debt instrument, stated interest rate

4.35%

Basis spread on federal funds rate

0.15%

Other_Comprehensive_Income_Acc

Other Comprehensive Income - Accumulated Other Comprehensive Loss (Income) (Detail) (USD $)	3 Months Ended				9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014		Sep. 30, 2013		Sep. 30, 2014		Sep. 30, 2013		Dec. 31, 2013
Other Comprehensive Income Loss [Line Items]	'		'		'		'		'
Unrealized gain (loss) on cash flow hedges, Gross	($0.30)		$1.10		($0.30)		$0.70		'
Reclassification from AOCI to net income, Gross	0.4	[1]	0.1	[1]	0.9	[1]	1	[1]	'
Gain (Loss) on cash flow hedges, Gross	0.1		1.2		0.6		1.7		'
Amortization of unrecognized benefit costs, Gross	0.4	[2]	1	[2]	2.4	[2]	3.2	[2]	'
Increase in unrecognized postemployment costs, Gross	0	[3]	'		-12.9	[3]	'		'
Change in benefit obligation due to remeasurement, Gross	-1.1		'		-1.1		'		'
Total other comprehensive income (loss), Gross	-0.6		4.8		-11		7.5		'
Recognized benefit costs due to settlement, Gross	'		2.6		'		2.6		'
Unrealized gain (loss) on cash flow hedges, Tax	0.1		-0.4		0.1		-0.3		'
Reclassification from AOCI to net income, Tax	-0.1	[1]	0	[1]	-0.3	[1]	-0.3	[1]	'
Gain (loss) on cash flow hedges, Tax	0		-0.4		-0.2		-0.6		'
Amortization of unrecognized benefit costs, Tax	-0.2	[2]	-0.4	[2]	-0.8	[2]	-1.2	[2]	'
Increase in unrecognized postemployment costs, Tax	0	[3]	'		4.7	[3]	'		'
Change in benefit obligation due to remeasurement, Tax	0.4		'		0.4		'		'
Total other comprehensive income (loss), Tax	0.2		-1.8		4.1		-2.8		'
Recognized benefit costs due to settlement, Tax	'		-1		'		-1		'
Unrealized gain (loss) on cash flow hedges, Net	-0.2		0.7		-0.2		0.4		'
Reclassification from AOCI to net income, Net	0.3	[1]	0.1	[1]	0.6	[1]	0.7	[1]	'
Gain (loss) on cash flow hedges, Net	0.1		0.8		0.4		1.1		'
Amortization of unrecognized benefit costs	0.2	[2]	0.6	[2]	1.6	[2]	2	[2]	'
Increase in unrecognized postemployment costs, Net	0	[3]	'		-8.2	[3]	'		'
Change in benefit obligation due to remeasurement, Net	-0.7		'		-0.7		'		'
Other comprehensive income (loss), net of tax	-0.4		3		-6.9		4.7		'
Recognized benefit costs due to settlement, Net	0		1.6		0		1.6		'
Unrecognized pension loss and prior service credit	-19.9	[4]	'		-19.9	[4]	'		-20.5	[4]
Unrecognized other benefit loss, prior service cost and transition obligation	7.2	[5]	'		7.2	[5]	'		15.1	[5]
Net unrealized losses from cash flow hedges	-7.4	[6]	'		-7.4	[6]	'		-7.8	[6]
Total accumulated other comprehensive loss	-20.1		'		-20.1		'		-13.2
Tampa Electric Company [Member]	'		'		'		'		'
Other Comprehensive Income Loss [Line Items]	'		'		'		'		'
Unrealized gain (loss) on cash flow hedges, Gross	0		0		0		0		'
Reclassification from AOCI to net income, Gross	0.4		0.4		0.8		1.1		'
Gain (Loss) on cash flow hedges, Gross	0.4		0.4		0.8		1.1		'
Total other comprehensive income (loss), Gross	0.4		0.4		0.8		1.1		'
Unrealized gain (loss) on cash flow hedges, Tax	0		0		0		0		'
Reclassification from AOCI to net income, Tax	-0.1		-0.2		-0.3		-0.4		'
Gain (loss) on cash flow hedges, Tax	-0.1		-0.2		-0.3		-0.4		'
Total other comprehensive income (loss), Tax	-0.1		-0.2		-0.3		-0.4		'
Unrealized gain (loss) on cash flow hedges, Net	0		0		0		0		'
Reclassification from AOCI to net income, Net	0.3		0.2		0.5		0.7		'
Gain (loss) on cash flow hedges, Net	0.3		0.2		0.5		0.7		'
Other comprehensive income (loss), net of tax	0.3		0.2		0.5		0.7		'
Net unrealized losses from cash flow hedges	-7.3	[7]	'		-7.3	[7]	'		-7.8	[7]
Total accumulated other comprehensive loss	($7.30)		'		($7.30)		'		($7.80)

[1]	Related to interest rate contracts recognized in Interest expense and commodity contracts recognized in Loss from discontinued operations
[2]	Related to postretirement and postemployment benefits. See Note 5 for additional information
[3]	Amounts reflect an out-of-period adjustment related to TECO Coal's unfunded black lung liability
[4]	Net of tax benefit of $12.3 million and $12.6 million as of Sept. 30, 2014 and Dec. 31, 2013, respectively.
[5]	Net of tax expense of $4.4 million and $9.1 million as of Sept. 30, 2014 and Dec. 31, 2013, respectively. Balance includes a $7.8 million loss related to TECO Coal's unfunded black lung liability that will be reclassified from AOCI to net income from discontinued operations upon the settlement of the black lung obligation at the sale date. See Note 18.
[6]	Net of tax benefit of $4.7 million and $4.9 million as of Sept. 30, 2014 and Dec. 31, 2013, respectively.
[7]	Net of tax benefit of $4.6 million and $4.9 million as of Sept.B 30, 2014 and Dec. 31, 2013, respectively.

Other_Comprehensive_Income_Acc1

Other Comprehensive Income - Accumulated Other Comprehensive Loss (Parenthetical) (Detail) (USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Accumulated Other Comprehensive Income Loss [Line Items]	'	'
Net income discontinued operations settlement	$7.80	'
Net unrealized losses from cash flow hedges, tax benefit	4.7	4.9
Pension Benefits [Member]	'	'
Accumulated Other Comprehensive Income Loss [Line Items]	'	'
Unrecognized pension and other benefit loss, prior service cost (credit) and transition obligation, tax expense (benefit)	12.3	12.6
Other Postretirement Benefits [Member]	'	'
Accumulated Other Comprehensive Income Loss [Line Items]	'	'
Unrecognized pension and other benefit loss, prior service cost (credit) and transition obligation, tax expense (benefit)	$4.40	$9.10

Earnings_Per_Share_Schedule_of

Earnings Per Share - Schedule of Earnings Per Share (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Basic earnings per share	'	'	'	'
Net income from continuing operations	$73	$64.30	$179	$153.30
Amount allocated to nonvested participating shareholders	-0.2	-0.2	-0.6	-0.5
Income before discontinued operations available to common shareholders - Basic	72.8	64.1	178.4	152.8
Income (Loss) from discontinued operations, net	-61.9	-1.5	-59.4	2.4
Amount allocated to nonvested participating shareholders	0	0	0	0
Income (Loss) from discontinued operations available to common shareholders - Basic	-61.9	-1.5	-59.4	2.4
Net income	11.1	62.8	119.6	155.7
Amount allocated to nonvested participating shareholders	-0.2	-0.2	-0.6	-0.5
Net income available to common shareholders - Basic	10.9	62.6	119	155.2
Average common shares outstanding - Basic	227.8	215.2	220.3	214.9
Earnings per share from continuing operations - Basic	$0.32	$0.30	$0.81	$0.71
Earnings per share from discontinued operations - Basic	($0.28)	($0.01)	($0.27)	$0.01
Earnings per share - Basic	$0.04	$0.29	$0.54	$0.72
Diluted earnings per share	'	'	'	'
Net income from continuing operations	73	64.3	179	153.3
Amount allocated to nonvested participating shareholders	-0.2	-0.2	-0.6	-0.5
Income before discontinued operations available to common shareholders - Diluted	72.8	64.1	178.4	152.8
Income (Loss) from discontinued operations, net	-61.9	-1.5	-59.4	2.4
Amount allocated to nonvested participating shareholders	0	0	0	0
Income (Loss) from discontinued operations available to common shareholders - Diluted	-61.9	-1.5	-59.4	2.4
Net income	11.1	62.8	119.6	155.7
Amount allocated to nonvested participating shareholders	-0.2	-0.2	-0.6	-0.5
Net income available to common shareholders - Diluted	$10.90	$62.60	$119	$155.20
Average common shares outstanding - Basic	227.8	215.2	220.3	214.9
Assumed conversion of stock options, unvested restricted stock and contingent performance shares, net	0.5	0.4	0.5	0.5
Average common shares outstanding - Diluted	228.3	215.6	220.8	215.4
Earnings per share from continuing operations - Diluted	$0.32	$0.30	$0.81	$0.71
Earnings per share from discontinued operations - Diluted	($0.28)	($0.01)	($0.27)	$0.01
Earnings per share - Diluted	$0.04	$0.29	$0.54	$0.72
Anti-dilutive shares	0	0	0	0

Commitments_and_Contingencies_1

Commitments and Contingencies - Additional Information (Detail) (USD $)	0 Months Ended	9 Months Ended		0 Months Ended	9 Months Ended
In Millions, unless otherwise specified	Feb. 08, 2011	Sep. 30, 2014	Mar. 31, 2011	Dec. 19, 2013	Sep. 30, 2014	Feb. 08, 2011	Sep. 30, 2014	Sep. 30, 2014
	SubrogationLawsuits	Claims	Customers	TECO Guatemala Holdings, LLC v. The Republic of Guatemala [Member]	TECO Guatemala Holdings, LLC v. The Republic of Guatemala [Member]	Gas Shortages [Member]	PGS [Member]	PGS [Member]
	InsuranceCarrier					Customers		Tampa Electric Company [Member]
Site Contingency [Line Items]	'	'	'	'	'	'	'	'
Gas supply disruption of high utility customers	'	'	32,000	'	'	28,700	'	'
Number of class dismissed	'	2	'	'	'	'	'	'
Period of appeal expires	'	'30 days	'	'	'	'	'	'
Right to appeal expiration date	'	'October 2014	'	'	'	'	'	'
Number of lawsuits for insurance carriers	2	'	'	'	'	'	'	'
Number of subrogation lawsuits	18	'	'	'	'	'	'	'
litigation settlement interest	'	'	'	'	'U.S. prime rate plus 2%.	'	'	'
litigation settlement amount	'	'	'	$7.50	'	'	'	'
Settlement agreement payment term	'	'	'	'	'120 days after the date of the Award	'	'	'
Duration of annulment proceedings	'	'2 years	'	'	'	'	'	'
Ultimate financial liability to superfund sites and former MGP sites	'	'	'	'	'	'	$33.30	$33.30

Commitments_and_Contingencies_2

Commitments and Contingencies - Letters of Credit and Guarantees (Detail) (USD $)	Sep. 30, 2014
In Millions, unless otherwise specified	Sep. 30, 2014
Guarantor Obligations [Line Items]	'
Year of expiration 2014	$0
Year of expiration 2015-2018	0.7
Year of expiration After 2018	96.9
Maximum Theoretical Obligation	97.6
Liabilities Recognized at Sep 30, 2014	0.1
TECO Coal [Member] \| Fuel Purchase Related [Member]	'
Guarantor Obligations [Line Items]	'
Year of expiration 2014	0
Year of expiration 2015-2018	0.7
Year of expiration After 2018	4
Maximum Theoretical Obligation	4.7
Liabilities Recognized at Sep 30, 2014	0
Other Subsidiaries [Member] \| Fuel Purchase / Energy Management [Member]	'
Guarantor Obligations [Line Items]	'
Year of expiration 2014	0
Year of expiration 2015-2018	0
Year of expiration After 2018	92.9
Maximum Theoretical Obligation	92.9
Liabilities Recognized at Sep 30, 2014	0.1
Tampa Electric Company [Member] \| Letters Of Credit [Member] \|	'
Guarantor Obligations [Line Items]	'
Year of expiration 2014	0
Year of expiration 2015-2018	0
Year of expiration After 2018	0.7
Maximum Theoretical Obligation	0.7
Liabilities Recognized at Sep 30, 2014	0.1
New Mexico Gas Company [Member] \| Letters Of Credit [Member] \|	'
Guarantor Obligations [Line Items]	'
Year of expiration 2014	0
Year of expiration 2015-2018	0
Year of expiration After 2018	1.7
Maximum Theoretical Obligation	1.7
Liabilities Recognized at Sep 30, 2014	$1.30

Segment_Information_Schedule_o

Segment Information - Schedule of Segment Information (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013	Jun. 30, 2014	Dec. 31, 2013
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Total revenues	$687.20	$642.10	$1,870.90	$1,792.90	'	'
Depreciation and amortization	78.6	76.1	230	222.8	'	'
Total interest charges	42.9	39.9	123.2	121.6	'	'
Provision for income taxes	33.7	38.9	98	91.4	'	'
Net income from continuing operations	73	64.3	179	153.3	'	'
Income from discontinued operations, net	-61.9	-1.5	-59.4	2.4	'	'
Net income	11.1	62.8	119.6	155.7	'	'
Income (Loss) from discontinued operations, net	-61.9	-1.5	-59.4	2.4	'	'
Goodwill	401.8	'	401.8	'	0	0
Assets held for sale, current	133.7	'	133.7	'	'	0
Assets held for sale, non-current	78.6	'	78.6	'	'	0
Total assets	8,653.60	'	8,653.60	'	'	7,448
Tampa Electric Company [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Total revenues	668.5	639.4	1,847.30	1,783.30	'	'
Depreciation and amortization	75.4	75.6	225.9	221.6	'	'
Total interest charges	27.3	26.2	79.4	79.6	'	'
Provision for income taxes	51.5	46.1	129.2	111.1	'	'
Net income	84.5	74.1	214	178.2	'	'
Total assets	7,154.30	6,875.80	7,154.30	6,875.80	'	6,875.80
Tampa Electric [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Total revenues	581.8	556.4	1,547.70	1,477.30	'	'
Depreciation and amortization	61.8	62.2	185.6	182	'	'
Total interest charges	23.8	22.8	69.1	69.5	'	'
Provision for income taxes	48.5	42.7	112.2	94	'	'
Net income	79.7	68.7	187.1	151.1	'	'
Total assets	6,160.80	5,895.40	6,160.80	5,895.40	'	'
People Gas [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Total revenues	86.9	83.4	300.6	307.1	'	'
Depreciation and amortization	13.6	13.4	40.3	39.6	'	'
Total interest charges	3.5	3.4	10.3	10.1	'	'
Provision for income taxes	3	3.4	17	17.1	'	'
Net income	4.8	5.4	26.9	27.1	'	'
Total assets	1,002.40	989.3	1,002.40	989.3	'	'
New Mexico Gas Company [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Total revenues	16.2	0	16.2	0	'	'
Depreciation and amortization	2.8	0	2.8	0	'	'
Total interest charges	1.1	0	1.1	0	'	'
Provision for income taxes	-0.5	0	-0.5	0	'	'
Net income from continuing operations	-0.9	0	-0.9	0	'	'
Income from discontinued operations, net	0	0	0	0	'	'
Net income	-0.9	0	-0.9	0	'	'
Income (Loss) from discontinued operations, net	0	0	0	0	'	'
Goodwill	401.8	'	401.8	'	'	'
Assets held for sale, current	0	'	0	'	'	'
Assets held for sale, non-current	0	'	0	'	'	'
Total assets	1,171.40	'	1,171.40	'	'	0
TECO Coal [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Total revenues	'	'	0	0	'	'
Depreciation and amortization	'	'	0	0	'	'
Total interest charges	'	'	0	0	'	'
Provision for income taxes	'	'	0	0	'	'
Net income from continuing operations	'	'	0	0	'	'
Income from discontinued operations, net	'	'	-65.6	2.3	'	'
Net income	'	'	-65.6	2.3	'	'
Income (Loss) from discontinued operations, net	'	'	-65.6	2.3	'	'
Goodwill	0	'	0	'	'	'
Assets held for sale, current	133.7	'	133.7	'	'	'
Assets held for sale, non-current	78.6	'	78.6	'	'	'
Total assets	261.8	'	261.8	'	'	316.3
Revenues - External [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Total revenues	687.2	642.1	1,870.90	1,792.90	'	'
Revenues - External [Member] \| Tampa Electric Company [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Total revenues	668.5	639.4	1,847.30	1,783.30	'	'
Revenues - External [Member] \| Tampa Electric [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Total revenues	581.6	556.3	1,547.30	1,477	'	'
Revenues - External [Member] \| People Gas [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Total revenues	86.9	83.1	300	306.3	'	'
Revenues - External [Member] \| New Mexico Gas Company [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Total revenues	16.2	0	16.2	0	'	'
Revenues - External [Member] \| TECO Coal [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Total revenues	'	'	0	0	'	'
Sales to Affiliates [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Sales to affiliates	0	0	0	0	'	'
Sales to Affiliates [Member] \| Tampa Electric Company [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Sales to affiliates	0	0	0	0	'	'
Sales to Affiliates [Member] \| Tampa Electric [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Sales to affiliates	0.2	0.1	0.4	0.3	'	'
Sales to Affiliates [Member] \| People Gas [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Sales to affiliates	0	0.3	0.6	0.8	'	'
Sales to Affiliates [Member] \| New Mexico Gas Company [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Sales to affiliates	0	0	0	0	'	'
Sales to Affiliates [Member] \| TECO Coal [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Sales to affiliates	'	'	0	0	'	'
Operating Segments [Member] \| Tampa Electric [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Total revenues	581.8	556.4	1,547.70	1,477.30	'	'
Depreciation and amortization	61.8	62.2	185.6	182	'	'
Total interest charges	23.8	22.8	69.1	69.5	'	'
Provision for income taxes	48.5	42.7	112.2	94	'	'
Net income from continuing operations	79.7	68.7	187.1	151.1	'	'
Income from discontinued operations, net	0	0	0	0	'	'
Net income	79.7	68.7	187.1	151.1	'	'
Income (Loss) from discontinued operations, net	0	0	0	0	'	'
Goodwill	0	'	0	'	'	'
Assets held for sale, current	0	'	0	'	'	'
Assets held for sale, non-current	0	'	0	'	'	'
Total assets	6,485.50	'	6,485.50	'	'	6,126.90
Operating Segments [Member] \| People Gas [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Total revenues	86.9	83.4	300.6	307.1	'	'
Depreciation and amortization	13.6	13.4	40.3	39.6	'	'
Total interest charges	3.5	3.4	10.3	10.1	'	'
Provision for income taxes	3	3.4	17	17.1	'	'
Net income from continuing operations	4.8	5.4	26.9	27.1	'	'
Income from discontinued operations, net	0	0	0	0	'	'
Net income	4.8	5.4	26.9	27.1	'	'
Income (Loss) from discontinued operations, net	0	0	0	0	'	'
Goodwill	0	'	0	'	'	'
Assets held for sale, current	0	'	0	'	'	'
Assets held for sale, non-current	0	'	0	'	'	'
Total assets	1,034.10	'	1,034.10	'	'	1,021.20
Operating Segments [Member] \| TECO Coal [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Total revenues	0	0	'	'	'	'
Depreciation and amortization	0	0	'	'	'	'
Total interest charges	0	0	'	'	'	'
Provision for income taxes	0	0	'	'	'	'
Net income from continuing operations	0	0	'	'	'	'
Income from discontinued operations, net	-64.8	-1.4	'	'	'	'
Net income	-64.8	-1.4	'	'	'	'
Income (Loss) from discontinued operations, net	-64.8	-1.4	'	'	'	'
Operating Segments [Member] \| Revenues - External [Member] \| Tampa Electric [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Total revenues	581.5	556.2	1,546.90	1,476.60	'	'
Operating Segments [Member] \| Revenues - External [Member] \| People Gas [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Total revenues	86.9	83.1	300	306.3	'	'
Operating Segments [Member] \| Revenues - External [Member] \| TECO Coal [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Total revenues	0	0	'	'	'	'
Operating Segments [Member] \| Sales to Affiliates [Member] \| Tampa Electric [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Sales to affiliates	0.3	0.2	0.8	0.7	'	'
Operating Segments [Member] \| Sales to Affiliates [Member] \| People Gas [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Sales to affiliates	0	0.3	0.6	0.8	'	'
Operating Segments [Member] \| Sales to Affiliates [Member] \| TECO Coal [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Sales to affiliates	0	0	'	'	'	'
Intersegment Eliminations	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Total revenues	2.3	2.3	6.4	8.5	'	'
Depreciation and amortization	0.4	0.5	1.3	1.2	'	'
Total interest charges	14.5	13.7	42.7	42	'	'
Provision for income taxes	-17.3	-7.2	-30.7	-19.7	'	'
Net income from continuing operations	-10.6	-9.8	-34.1	-24.9	'	'
Income from discontinued operations, net	2.9	-0.1	6.2	0.1	'	'
Net income	-7.7	-9.9	-27.9	-24.8	'	'
Income (Loss) from discontinued operations, net	2.9	-0.1	6.2	0.1	'	'
Goodwill	0	'	0	'	'	'
Assets held for sale, current	0	'	0	'	'	'
Assets held for sale, non-current	0	'	0	'	'	'
Total assets	-299.2	'	-299.2	'	'	-16.4
Intersegment Eliminations \| Tampa Electric Company [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Total revenues	-0.2	-0.4	-1	-1.1	'	'
Depreciation and amortization	0	0	0	0	'	'
Total interest charges	0	0	0	0	'	'
Provision for income taxes	0	0	0	0	'	'
Net income	0	0	0	0	'	'
Total assets	-8.9	-8.9	-8.9	-8.9	'	'
Intersegment Eliminations \| Revenues - External [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Total revenues	2.6	2.8	7.8	10	'	'
Intersegment Eliminations \| Revenues - External [Member] \| Tampa Electric Company [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Total revenues	0	0	0	0	'	'
Intersegment Eliminations \| Sales to Affiliates [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Sales to affiliates	-0.3	-0.5	-1.4	-1.5	'	'
Intersegment Eliminations \| Sales to Affiliates [Member] \| Tampa Electric Company [Member]	'	'	'	'	'	'
Segment Reporting Information [Line Items]	'	'	'	'	'	'
Sales to affiliates	($0.20)	($0.40)	($1)	($1.10)	'	'

Accounting_for_Derivative_Inst2

Accounting for Derivative Instruments and Hedging Activities - Derivatives Designated as Cash Flow Hedges (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Derivatives Fair Value [Line Items]	'	'
Derivative assets	$0.20	$9.70
Derivative assets	0	0.3
Total assets	0.2	10
Derivative liabilities	4.1	0.1
Long-term liabilities	1.6	0.2
Total liabilities	5.7	0.3
Derivative liabilities	1.6	0.2
Tampa Electric Company [Member]	'	'
Derivatives Fair Value [Line Items]	'	'
Derivative assets	0.1	9.5
Derivative assets	0	0.3
Total assets	0.1	9.8
Derivative liabilities	4	0
Long-term liabilities	1.6	0.2
Total liabilities	5.6	0.2
Derivative liabilities	1.6	0.2
Tampa Electric Company [Member] \| Natural Gas Derivatives [Member]	'	'
Derivatives Fair Value [Line Items]	'	'
Derivative assets	0.1	9.5
Derivative assets	0	0.3
Total assets	0.1	9.8
Derivative liabilities	4	0
Long-term liabilities	1.6	0.2
Total liabilities	5.6	0.2
Derivative liabilities	$1.60	$0.20

Accounting_for_Derivative_Inst3

Accounting for Derivative Instruments and Hedging Activities - Additional Information (Detail) (USD $)	9 Months Ended
	Sep. 30, 2014		Dec. 31, 2013
Derivative [Line Items]	'		'
Collateral posted with or received from any counterparties	$0		$0
Net loss related to cash flow hedges and interest rate swaps in AOCI, after tax	7,400,000	[1]	7,800,000	[1]
Diesel Fuel [Member]	'		'
Derivative [Line Items]	'		'
Maximum length of time hedging in future cash flow	31-Dec-14		'
Natural Gas Contracts [Member]	'		'
Derivative [Line Items]	'		'
Maximum length of time hedging in future cash flow	31-Dec-16		'
Tampa Electric Company [Member]	'		'
Derivative [Line Items]	'		'
Net loss related to cash flow hedges and interest rate swaps in AOCI, after tax	7,300,000	[2]	7,800,000	[2]
Net pretax gain (loss) expected to be reclassified from regulatory assets or liabilities	-3,900,000		'
Interest Rate Swap [Member]	'		'
Derivative [Line Items]	'		'
Net loss related to cash flow hedges and interest rate swaps in AOCI, after tax	7,400,000		7,800,000
Interest Rate Swap [Member] \| Tampa Electric Company [Member]	'		'
Derivative [Line Items]	'		'
Net loss related to cash flow hedges and interest rate swaps in AOCI, after tax	$7,300,000		$7,800,000

[1]	Net of tax benefit of $4.7 million and $4.9 million as of Sept. 30, 2014 and Dec. 31, 2013, respectively.
[2]	Net of tax benefit of $4.6 million and $4.9 million as of Sept.B 30, 2014 and Dec. 31, 2013, respectively.

Accounting_for_Derivative_Inst4

Accounting for Derivative Instruments and Hedging Activities - Gross Amounts of Derivatives and Their Related Offset Amounts (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Derivative [Line Items]	'	'
Derivative assets, Gross Amounts of Recognized Assets	$1.40	$10.50
Derivative assets, Gross Amounts offset on the Balance Sheet	-1.2	-0.5
Derivative assets, Net Amounts of Assets	0.2	10
Derivative liabilities, Gross Amounts of Recognized (Liabilities)	-6.9	-0.8
Derivative liabilities, Gross Amounts offset on the Balance Sheet	1.2	0.5
Derivative assets, Net Amounts of Liabilities	-5.7	-0.3
Tampa Electric Company [Member]	'	'
Derivative [Line Items]	'	'
Derivative assets, Gross Amounts of Recognized Assets	1.4	10.3
Derivative assets, Gross Amounts offset on the Balance Sheet	-1.3	-0.5
Derivative assets, Net Amounts of Assets	0.1	9.8
Derivative liabilities, Gross Amounts of Recognized (Liabilities)	-6.9	-0.7
Derivative liabilities, Gross Amounts offset on the Balance Sheet	1.3	0.5
Derivative assets, Net Amounts of Liabilities	($5.60)	($0.20)

Accounting_for_Derivative_Inst5

Accounting for Derivative Instruments and Hedging Activities - Derivatives Designated as Hedging Instruments (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Derivatives Fair Value [Line Items]	'	'
Derivative assets	$0.20	$9.70
Long-term derivative assets	0	0.3
Derivative assets, Net Amounts of Assets	0.2	10
Derivative liabilities	4.1	0.1
Long-term liabilities	1.6	0.2
Total liabilities	5.7	0.3
Derivative assets	0	0.3
Derivative liabilities	1.6	0.2
Natural Gas Contracts [Member]	'	'
Derivatives Fair Value [Line Items]	'	'
Derivative assets	0.1	9.5
Long-term derivative assets	0	0.3
Derivative assets, Net Amounts of Assets	0.1	9.8
Derivative liabilities	4	0
Long-term liabilities	1.6	0.2
Total liabilities	5.6	0.2
Derivative assets	0	0.3
Derivative liabilities	1.6	0.2
Derivatives Designated as Hedging Instruments [Member]	'	'
Derivatives Fair Value [Line Items]	'	'
Derivative assets, Net Amounts of Assets	0.2	10
Total liabilities	5.7	0.3
Diesel Fuel Derivatives [Member]	'	'
Derivatives Fair Value [Line Items]	'	'
Derivative assets	0.1	0.2
Long-term derivative assets	0	0
Derivative assets, Net Amounts of Assets	0.1	0.2
Derivative liabilities	0.1	0.1
Long-term liabilities	0	0
Total liabilities	0.1	0.1
Derivative assets	0	0
Derivative liabilities	0	0
Diesel Fuel Derivatives [Member] \| Derivatives Designated as Hedging Instruments [Member]	'	'
Derivatives Fair Value [Line Items]	'	'
Derivative assets	0.1	0.2
Long-term derivative assets	0	0
Derivative liabilities	0.1	0.1
Long-term liabilities	0	0
Derivative assets	0	0
Derivative liabilities	0	0
Natural Gas Derivatives [Member] \| Derivatives Designated as Hedging Instruments [Member]	'	'
Derivatives Fair Value [Line Items]	'	'
Derivative assets	0.1	9.5
Long-term derivative assets	0	0.3
Derivative liabilities	4	0
Long-term liabilities	1.6	0.2
Derivative assets	0	0.3
Derivative liabilities	$1.60	$0.20

Accounting_for_Derivative_Inst6

Accounting for Derivative Instruments and Hedging Activities - Energy Related Derivatives (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Derivatives Fair Value [Line Items]	'	'
Regulatory liabilities	$65.80	$85.80
Regulatory liabilities	727.2	631.4
Regulatory liabilities	793	717.2
Regulatory assets	24.3	34.3
Long-term regulatory assets	342.2	293.1
Regulatory assets	366.5	327.4
Regulatory assets	342.2	293.1
Tampa Electric Company [Member]	'	'
Derivatives Fair Value [Line Items]	'	'
Regulatory liabilities	64.5	85.8
Regulatory liabilities	623.5	631.4
Regulatory liabilities	688	717.2
Regulatory assets	22.9	34.3
Long-term regulatory assets	311.7	293.1
Regulatory assets	334.6	327.4
Regulatory assets	311.7	293.1
Energy Related Derivatives [Member]	'	'
Derivatives Fair Value [Line Items]	'	'
Regulatory liabilities	0.1	9.5
Regulatory liabilities	0	0.3
Regulatory liabilities	0.1	9.8
Regulatory assets	4	0
Long-term regulatory assets	1.6	0.2
Regulatory assets	5.6	0.2
Regulatory assets	1.6	0.2
Energy Related Derivatives [Member] \| Tampa Electric Company [Member]	'	'
Derivatives Fair Value [Line Items]	'	'
Regulatory liabilities	0.1	9.5
Regulatory liabilities	0	0.3
Regulatory liabilities	0.1	9.8
Regulatory assets	4	0
Long-term regulatory assets	1.6	0.2
Regulatory assets	5.6	0.2
Regulatory assets	$1.60	$0.20

Accounting_for_Derivative_Inst7

Accounting for Derivative Instruments and Hedging Activities - Effect of Hedging Instruments on Other Comprehensive Income and Income (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Derivative Instruments Gain Loss [Line Items]	'	'	'	'
Amount of Gain/(Loss) on Derivatives Recognized in OCI	($0.20)	$0.70	($0.20)	$0.40
Amount of Gain/(Loss) Reclassified From AOCI Into Income	-0.3	-0.1	-0.6	-0.7
Tampa Electric Company [Member]	'	'	'	'
Derivative Instruments Gain Loss [Line Items]	'	'	'	'
Amount of Gain/(Loss) Reclassified From AOCI Into Income	-0.3	-0.2	-0.5	-0.7
Diesel Fuel Derivatives [Member]	'	'	'	'
Derivative Instruments Gain Loss [Line Items]	'	'	'	'
Amount of Gain/(Loss) on Derivatives Recognized in OCI	-0.2	0.7	-0.2	0.4
Location of Gain/(Loss) Reclassified From AOCI Into Income	'Loss from discontinued operations	'Loss from discontinued operations	'Loss from discontinued operations	'Loss from discontinued operations
Amount of Gain/(Loss) Reclassified From AOCI Into Income	0	0.1	-0.1	0
Interest rate contracts [Member]	'	'	'	'
Derivative Instruments Gain Loss [Line Items]	'	'	'	'
Amount of Gain/(Loss) on Derivatives Recognized in OCI	0	0	0	0
Location of Gain/(Loss) Reclassified From AOCI Into Income	'Interest expense	'Interest expense	'Interest expense	'Interest expense
Amount of Gain/(Loss) Reclassified From AOCI Into Income	-0.3	-0.2	-0.5	-0.7
Interest rate contracts [Member] \| Tampa Electric Company [Member]	'	'	'	'
Derivative Instruments Gain Loss [Line Items]	'	'	'	'
Amount of Gain/(Loss) Reclassified From AOCI Into Income	($0.30)	($0.20)	($0.50)	($0.70)

Accounting_for_Derivative_Inst8

Accounting for Derivative Instruments and Hedging Activities - Derivative Activity for Instruments Classified as Qualifying Cash Flow Hedges (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Derivative Instruments Gain Loss [Line Items]	'	'	'	'
Fair Value Asset/(Liability)	$0	$0.10	$0	$0.10
Amount of Gain/(Loss) on Derivatives Recognized in OCI	-0.2	0.7	-0.2	0.4
Amount of Gain/(Loss) Reclassified From AOCI Into Income	-0.3	-0.1	-0.6	-0.7
Diesel Fuel Derivatives [Member]	'	'	'	'
Derivative Instruments Gain Loss [Line Items]	'	'	'	'
Fair Value Asset/(Liability)	0	0.1	0	0.1
Amount of Gain/(Loss) on Derivatives Recognized in OCI	-0.2	0.7	-0.2	0.4
Amount of Gain/(Loss) Reclassified From AOCI Into Income	0	0.1	-0.1	0
Interest Rate Swap [Member]	'	'	'	'
Derivative Instruments Gain Loss [Line Items]	'	'	'	'
Fair Value Asset/(Liability)	0	0	0	0
Amount of Gain/(Loss) on Derivatives Recognized in OCI	'	'	0	0
Amount of Gain/(Loss) Reclassified From AOCI Into Income	'	'	($0.50)	($0.70)

Accounting_for_Derivative_Inst9

Accounting for Derivative Instruments and Hedging Activities - Derivative Volumes Expected to Settle (Detail)	Sep. 30, 2014
	gal
Diesel Fuel Derivatives [Member] \| Physical [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	0
Derivative, Nonmonetary Notional Amount	0
Diesel Fuel Derivatives [Member] \| Financial [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	500,000
Derivative, Nonmonetary Notional Amount	500,000
Diesel Fuel Derivatives [Member] \| 2014 [Member] \| Physical [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	0
Derivative, Nonmonetary Notional Amount	0
Diesel Fuel Derivatives [Member] \| 2014 [Member] \| Financial [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	500,000
Derivative, Nonmonetary Notional Amount	500,000
Diesel Fuel Derivatives [Member] \| 2015 [Member] \| Physical [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	0
Derivative, Nonmonetary Notional Amount	0
Diesel Fuel Derivatives [Member] \| 2015 [Member] \| Financial [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	0
Derivative, Nonmonetary Notional Amount	0
Diesel Fuel Derivatives [Member] \| 2016 [Member] \| Physical [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	0
Derivative, Nonmonetary Notional Amount	0
Diesel Fuel Derivatives [Member] \| 2016 [Member] \| Financial [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	0
Derivative, Nonmonetary Notional Amount	0
Natural Gas Contracts [Member] \| Physical [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	0
Derivative, Nonmonetary Notional Amount	0
Natural Gas Contracts [Member] \| Physical [Member] \| Tampa Electric Company [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	0
Derivative, Nonmonetary Notional Amount	0
Natural Gas Contracts [Member] \| Financial [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	51,400,000
Derivative, Nonmonetary Notional Amount	51,400,000
Natural Gas Contracts [Member] \| Financial [Member] \| Tampa Electric Company [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	51,400,000
Derivative, Nonmonetary Notional Amount	51,400,000
Natural Gas Contracts [Member] \| 2014 [Member] \| Physical [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	0
Derivative, Nonmonetary Notional Amount	0
Natural Gas Contracts [Member] \| 2014 [Member] \| Physical [Member] \| Tampa Electric Company [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	0
Derivative, Nonmonetary Notional Amount	0
Natural Gas Contracts [Member] \| 2014 [Member] \| Financial [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	11,600,000
Derivative, Nonmonetary Notional Amount	11,600,000
Natural Gas Contracts [Member] \| 2014 [Member] \| Financial [Member] \| Tampa Electric Company [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	11,600,000
Derivative, Nonmonetary Notional Amount	11,600,000
Natural Gas Contracts [Member] \| 2015 [Member] \| Physical [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	0
Derivative, Nonmonetary Notional Amount	0
Natural Gas Contracts [Member] \| 2015 [Member] \| Physical [Member] \| Tampa Electric Company [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	0
Derivative, Nonmonetary Notional Amount	0
Natural Gas Contracts [Member] \| 2015 [Member] \| Financial [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	32,200,000
Derivative, Nonmonetary Notional Amount	32,200,000
Natural Gas Contracts [Member] \| 2015 [Member] \| Financial [Member] \| Tampa Electric Company [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	32,200,000
Derivative, Nonmonetary Notional Amount	32,200,000
Natural Gas Contracts [Member] \| 2016 [Member] \| Physical [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	0
Derivative, Nonmonetary Notional Amount	0
Natural Gas Contracts [Member] \| 2016 [Member] \| Physical [Member] \| Tampa Electric Company [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	0
Derivative, Nonmonetary Notional Amount	0
Natural Gas Contracts [Member] \| 2016 [Member] \| Financial [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	7,600,000
Derivative, Nonmonetary Notional Amount	7,600,000
Natural Gas Contracts [Member] \| 2016 [Member] \| Financial [Member] \| Tampa Electric Company [Member]	'
Derivative [Line Items]	'
Derivative, Nonmonetary Notional Amount	7,600,000
Derivative, Nonmonetary Notional Amount	7,600,000

Fair_Value_Measurements_Schedu

Fair Value Measurements - Schedule of Recurring Fair Value Measurements (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	$0.20	$10
Total Swap Liabilities	5.7	0.3
Tampa Electric Company [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0.1	9.8
Total Swap Liabilities	5.6	0.2
Natural Gas Derivatives [Member] \| Tampa Electric Company [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0.1	9.8
Total Swap Liabilities	5.6	0.2
Diesel Fuel Derivatives [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0.1	0.2
Total Swap Liabilities	0.1	0.1
Fair Value, Measurements, Recurring [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0.2	'
Total Swap Liabilities	5.7	'
Fair Value, Measurements, Recurring [Member] \| Tampa Electric Company [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0.1	9.8
Total Swap Liabilities	5.6	0.2
Fair Value, Measurements, Recurring [Member] \| Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0	'
Total Swap Liabilities	0	'
Fair Value, Measurements, Recurring [Member] \| Level 1 [Member] \| Tampa Electric Company [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0	0
Total Swap Liabilities	0	0
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0.2	'
Total Swap Liabilities	5.7	'
Fair Value, Measurements, Recurring [Member] \| Level 2 [Member] \| Tampa Electric Company [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0.1	9.8
Total Swap Liabilities	5.6	0.2
Fair Value, Measurements, Recurring [Member] \| Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0	'
Total Swap Liabilities	0	'
Fair Value, Measurements, Recurring [Member] \| Level 3 [Member] \| Tampa Electric Company [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0	0
Total Swap Liabilities	0	0
Fair Value, Measurements, Recurring [Member] \| Natural Gas Derivatives [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0.1	'
Total Swap Liabilities	5.6	'
Fair Value, Measurements, Recurring [Member] \| Natural Gas Derivatives [Member] \| Tampa Electric Company [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0.1	9.8
Total Swap Liabilities	5.6	0.2
Fair Value, Measurements, Recurring [Member] \| Natural Gas Derivatives [Member] \| Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0	'
Total Swap Liabilities	0	'
Fair Value, Measurements, Recurring [Member] \| Natural Gas Derivatives [Member] \| Level 1 [Member] \| Tampa Electric Company [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0	0
Total Swap Liabilities	0	0
Fair Value, Measurements, Recurring [Member] \| Natural Gas Derivatives [Member] \| Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0.1	'
Total Swap Liabilities	5.6	'
Fair Value, Measurements, Recurring [Member] \| Natural Gas Derivatives [Member] \| Level 2 [Member] \| Tampa Electric Company [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0.1	9.8
Total Swap Liabilities	5.6	0.2
Fair Value, Measurements, Recurring [Member] \| Natural Gas Derivatives [Member] \| Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0	'
Total Swap Liabilities	0	'
Fair Value, Measurements, Recurring [Member] \| Natural Gas Derivatives [Member] \| Level 3 [Member] \| Tampa Electric Company [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0	0
Total Swap Liabilities	0	0
Fair Value, Measurements, Recurring [Member] \| Diesel Fuel Derivatives [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0.1	'
Total Swap Liabilities	0.1	'
Fair Value, Measurements, Recurring [Member] \| Diesel Fuel Derivatives [Member] \| Level 1 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0	'
Total Swap Liabilities	0	'
Fair Value, Measurements, Recurring [Member] \| Diesel Fuel Derivatives [Member] \| Level 2 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0.1	'
Total Swap Liabilities	0.1	'
Fair Value, Measurements, Recurring [Member] \| Diesel Fuel Derivatives [Member] \| Level 3 [Member]	'	'
Fair Value, Assets and Liabilities Measured on Recurring Basis [Line Items]	'	'
Total Swap Assets	0	'
Total Swap Liabilities	$0	'

Fair_Value_Measurements_Additi

Fair Value Measurements - Additional Information (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]	'	'
Total Swap Assets	$0.20	$10
Total Swap Liabilities	5.7	0.3
Tampa Electric Company [Member]	'	'
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]	'	'
Total Swap Assets	0.1	9.8
Total Swap Liabilities	5.6	0.2
Fair Value, Measurements, Recurring [Member]	'	'
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]	'	'
Total Swap Assets	0.2	'
Total Swap Liabilities	5.7	'
Fair Value, Measurements, Recurring [Member] \| Tampa Electric Company [Member]	'	'
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]	'	'
Total Swap Assets	0.1	9.8
Total Swap Liabilities	5.6	0.2
Fair Value, Measurements, Recurring [Member] \| Level 3 [Member]	'	'
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]	'	'
Total Swap Assets	0	'
Total Swap Liabilities	0	'
Fair Value, Measurements, Recurring [Member] \| Level 3 [Member] \| Tampa Electric Company [Member]	'	'
Fair Value Assets Liabilities Measured On Recurring Basis [Line Items]	'	'
Total Swap Assets	0	0
Total Swap Liabilities	$0	$0

Variable_Interest_Entities_Add

Variable Interest Entities - Additional Information (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Long Term Contract For Purchase Of Electric Power [Line Items]	'	'	'	'
Purchased power	$21	$15.70	$59.10	$50.80
Tampa Electric Company [Member]	'	'	'	'
Long Term Contract For Purchase Of Electric Power [Line Items]	'	'	'	'
Purchased power	21	15.7	59.1	50.8
Power Purchase Agreements [Member] \| Variable Interest Entities [Member]	'	'	'	'
Long Term Contract For Purchase Of Electric Power [Line Items]	'	'	'	'
Purchased power	8.1	6.5	20.9	16.4
Power Purchase Agreements [Member] \| Variable Interest Entities [Member] \| Tampa Electric Company [Member]	'	'	'	'
Long Term Contract For Purchase Of Electric Power [Line Items]	'	'	'	'
Purchased power	$8.10	$6.50	$20.90	$16.40
Minimum [Member]	'	'	'	'
Long Term Contract For Purchase Of Electric Power [Line Items]	'	'	'	'
Multiple PPAs range	'	'	117	'
Minimum [Member] \| Tampa Electric Company [Member]	'	'	'	'
Long Term Contract For Purchase Of Electric Power [Line Items]	'	'	'	'
Multiple PPAs range	'	'	117	'
Maximum [Member]	'	'	'	'
Long Term Contract For Purchase Of Electric Power [Line Items]	'	'	'	'
Multiple PPAs range	'	'	160	'
Maximum [Member] \| Tampa Electric Company [Member]	'	'	'	'
Long Term Contract For Purchase Of Electric Power [Line Items]	'	'	'	'
Multiple PPAs range	'	'	160	'

Discontinued_Operations_Assets2

Discontinued Operations, Assets Held for Sale and Asset Impairments Sale - Additional Information (Detail) (TECO Coal [Member], USD $)	9 Months Ended	0 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Oct. 17, 2014	Oct. 17, 2014
		Subsequent Event [Member]	Subsequent Event [Member]
			Maximum [Member]
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]	'	'	'
Impairment of held for sale asset	$98.40	'	'
Ownership interest sold	'	120	'
Contingent payments	'	'	$50

Discontinued_Operations_Assets3

Discontinued Operations, Assets Held for Sale and Asset Impairments Sale (Carrying Amount of Assets and Liabilities Held for Sale) (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]	'	'
Current assets	$133.70	$0
Property, plant and equipment, net and other long-term assets	78.6	0
Current liabilities	41.1	0
Long-term liabilities	64.4	0
TECO Coal [Member]	'	'
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]	'	'
Current assets	133.7	'
Property, plant and equipment, net and other long-term assets	78.6	'
Total assets held for sale	212.3	'
Current liabilities	41.1	'
Long-term liabilities	64.4	'
Total liabilities associated with assets held for sale	$105.50	'

Discontinued_Operations_Assets4

Discontinued Operations, Assets Held for Sale and Asset Impairments Sale - Components of Discontinued Operations (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]	'	'	'	'
(Loss) Income from discontinued operations	($98.80)	($2.90)	($97.60)	$0
(Benefit) Provision for income taxes	-36.9	-1.4	-38.2	-2.4
Loss on discontinued operations, net	-61.9	-1.5	-59.4	2.4
TECO Coal and TECO Guatemala [Member]	'	'	'	'
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]	'	'	'	'
Revenues	101.6	123.7	328.3	370
(Loss) Income from operations	-0.4	-2.9	0.8	0
(Loss) on impairment	-98.4	0	-98.4	0
(Loss) Income from discontinued operations	-98.8	-2.9	-97.6	0
(Benefit) Provision for income taxes	-36.9	-1.4	-38.2	-2.4
Loss on discontinued operations, net	($61.90)	($1.50)	($59.40)	$2.40

Discontinued_Operations_Assets5

Discontinued Operations, Assets Held for Sale and Asset Impairments Sale - Components of Discontinued Operations (Parenthetical) (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]	'	'	'	'
Loss from discontinued operations	($98.80)	($2.90)	($97.60)	$0
(Benefit) Provision for income taxes	-36.9	-1.4	-38.2	-2.4
TECO Guatemala [Member]	'	'	'	'
Income Statement Balance Sheet And Additional Disclosures By Disposal Groups Including Discontinued Operations [Line Items]	'	'	'	'
(Loss) Income from operations	'	-0.2	5	'
Loss from discontinued operations	'	-0.2	5	'
(Benefit) Provision for income taxes	'	($0.10)	$1.90	'

Acquisition_of_New_Mexico_Gas_2

Acquisition of New Mexico Gas Intermediate - Additional Information (Detail) (USD $)

3 Months Ended

9 Months Ended

0 Months Ended

9 Months Ended

0 Months Ended

3 Months Ended

9 Months Ended

3 Months Ended

9 Months Ended

In Millions, unless otherwise specified

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 30, 2013

Sep. 30, 2014

Sep. 02, 2014

Sep. 30, 2014

Sep. 02, 2014

Sep. 30, 2014

TECO Energy [Member]

NMGI [Member]

NMGC [Member]

NMGI and NMGC [Member]

Employee

Customers

Tax Non Deductible [Member]

Employee

Business Acquisition [Line Items]

Business acquisition, effective date

2-Sep-14

Aggregate Purchase Price

$950

Senior Secured Notes

200

Number of employees

720

Minimum number of customers served

513,000

Customer rate of credit

Increase in rate of credit

Goodwill expected tax deductible amount

146.1

Revenue

16.2

Net income

-2

After-tax non-recurring acquisition consummation, integration and other costs

0.9

2.1

5.7

3.9

Goodwill acquired in business acquisition

401.8

255.7

Obligations associated with severance benefits costs

$2.20

Acquisition_of_New_Mexico_Gas_3

Acquisition of New Mexico Gas Intermediate - Consideration in Acquisition (Detail) (NMGI [Member], USD $)	0 Months Ended
In Millions, unless otherwise specified	Sep. 02, 2014
NMGI [Member]	'
Business Acquisition [Line Items]	'
Cash	$530.10
Long-term debt assumed or settled, including accrued interest and fees	419.9
Total consideration transferred, excluding cash and working capital adjustments	$950

Acquisition_of_New_Mexico_Gas_4

Acquisition of New Mexico Gas Intermediate - Preliminary Purchase Price Allocation (Detail) (USD $)	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013	Sep. 02, 2014
In Millions, unless otherwise specified	Sep. 30, 2014	Jun. 30, 2014	Dec. 31, 2013	NMGI and NMGC [Member]
Business Acquisition [Line Items]	'	'	'	'
Current assets	'	'	'	$48.70
Property, plant and equipment	'	'	'	618.9
OPEB regulatory asset	'	'	'	6.4
Debt-related regulatory asset	'	'	'	23.9
Goodwill	401.8	0	0	401.8
Deferred tax assets	'	'	'	52.8
Other assets	'	'	'	30.2
Total assets	'	'	'	1,182.70
Current liabilities	'	'	'	-35
Long-term debt fair value adjustment and interest assumed	'	'	'	-22.7
Cost of removal regulatory liability	'	'	'	-100.6
Deferred tax liabilities	'	'	'	-60.8
OPEB liability	'	'	'	-9.8
Deferred credits and other liabilities	'	'	'	-3.8
Total liabilities	'	'	'	-232.7
Total purchase price allocation, excluding cash and working capital adjustments	'	'	'	$950

Acquisition_of_New_Mexico_Gas_5

Acquisition of New Mexico Gas Intermediate - Preliminary Purchase Price Allocation (Parenthetical) (Detail) (NMGI and NMGC [Member], USD $)	Sep. 02, 2014
In Millions, unless otherwise specified	Sep. 02, 2014
NMGI and NMGC [Member]	'
Business Acquisition [Line Items]	'
Accounts receivables	$18.90
Gross contract value	19.6
Contractual receivables not expected to be collected	$0.70

Acquisition_of_New_Mexico_Gas_6

Acquisition of New Mexico Gas Intermediate - Pro Forma Financial Information (Detail) (USD $)	3 Months Ended		9 Months Ended
In Millions, except Per Share data, unless otherwise specified	Sep. 30, 2014	Sep. 30, 2013	Sep. 30, 2014	Sep. 30, 2013
Business Combinations [Abstract]	'	'	'	'
Revenues	$720	$684.50	$2,111	$2,024.10
Net income from continuing operations	$70.80	$64.90	$199.30	$171.40
Basic and Diluted EPS from continuing operations	$0.31	$0.28	$0.86	$0.74

Acquisition_of_New_Mexico_Gas_7

Acquisition of New Mexico Gas Intermediate - Schedule of Goodwill (Detail) (USD $)	3 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Business Combination Segment Allocation [Line Items]	'	'
Balance as of Jul 1, 2014	$0	$0
Goodwill acquired in business acquisition	401.8	'
Balance as of Sep 30, 2014	401.8	0
NMGC [Member]	'	'
Business Combination Segment Allocation [Line Items]	'	'
Balance as of Jul 1, 2014	0	'
Goodwill acquired in business acquisition	401.8	'
Balance as of Sep 30, 2014	$401.80	'

Acquisition_of_New_Mexico_Gas_8

Acquisition of New Mexico Gas Intermediate - Intangible Assets and Liabilities Acquired Through Acquisition Included in Consolidated Balance Sheets, Along with Future Estimated Amortization (Detail) (Rights-of-way [Member], USD $)	9 Months Ended
In Millions, unless otherwise specified	Sep. 30, 2014
Rights-of-way [Member]	'
Acquired Finite Lived Intangible Assets [Line Items]	'
Weighted average amortization (years)	'17 years
Gross	$27.20
Accumulated amortization	-0.1
Net	27.1
2014	0.3
2015	1.4
2016	1.4
2017	1.4
2018	1.4
2019 and beyond	$21.20

Common_Stock_Additional_Inform

Common Stock - Additional Information (Detail) (Underwriter [Member], USD $)	1 Months Ended
In Millions, except Share data, unless otherwise specified	Jul. 31, 2014
Underwriter [Member]	'
Class Of Stock [Line Items]	'
Number of shares issued through underwriting agreement	15,500,000
Shares offered, price per share	$18.10
Additional shares to be offered under underwriting agreement	2,300,000
Number of days option granted to underwriters	'30 days
Proceeds from issuance to underwriters	$21
Underwriters exercised this option for an additional, shares	1,200,000
Net proceeds from offering through the underwriting	$271

Subsequent_Events_Additional_I

Subsequent Events - Additional Information (Detail) (USD $)	0 Months Ended
In Millions, unless otherwise specified	Feb. 08, 2011	Oct. 17, 2014	Oct. 17, 2014
	NMGC 2011 Notes [Member]	Subsequent Event [Member]	Subsequent Event [Member]
		TECO Coal [Member]	TECO Coal [Member]
			Maximum [Member]
Subsequent Event [Line Items]	'	'	'
Ownership interest sold	'	$120	'
Contingent payments	'	'	50
Aggregate principal amount issued	$200	'	'
Issuance of notes, maturity year	8-Feb-21	'	'

Other_Comprehensive_Income_Acc2

Other Comprehensive Income - Accumulated Other Comprehensive Loss (Income) (Parenthetical) (Detail) (USD $)	Sep. 30, 2014	Dec. 31, 2013
In Millions, unless otherwise specified	Sep. 30, 2014	Dec. 31, 2013
Other Comprehensive Income Loss [Line Items]	'	'
Net unrealized losses from cash flow hedges, tax benefit	$4.70	$4.90
Tampa Electric Company [Member]	'	'
Other Comprehensive Income Loss [Line Items]	'	'
Net unrealized losses from cash flow hedges, tax benefit	$4.60	$4.90