Employee Postretirement Benefits - Schedule of Fair Value Hierarchy Plan's Investments (Detail) - USD ($) $ in Thousands	Dec. 31, 2015	Dec. 31, 2014
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 625,400	$ 648,000
Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	625,400	648,000
Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,900	400
Cash [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,900	400
Net Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(11,000)	(3,500)
Net Cash [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(11,000)	(3,500)
Using NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	377,200	406,700
Using NAV [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	377,200	406,700
Using NAV [Member] | Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Using NAV [Member] | Cash [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Using NAV [Member] | Net Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Using NAV [Member] | Net Cash [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Accounts Receivable [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14,300	1,400
Accounts Receivable [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14,300	1,400
Accounts Receivable [Member] | Using NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Accounts Receivable [Member] | Using NAV [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Accounts Payable [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(27,200)	(5,300)
Accounts Payable [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(27,200)	(5,300)
Accounts Payable [Member] | Using NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Accounts Payable [Member] | Using NAV [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	90,400	99,100
Level 1 [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	90,400	99,100
Level 1 [Member] | Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,900	400
Level 1 [Member] | Cash [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,900	400
Level 1 [Member] | Net Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(11,000)	(3,500)
Level 1 [Member] | Net Cash [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(11,000)	(3,500)
Level 1 [Member] | Accounts Receivable [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14,300	1,400
Level 1 [Member] | Accounts Receivable [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	14,300	1,400
Level 1 [Member] | Accounts Payable [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(27,200)	(5,300)
Level 1 [Member] | Accounts Payable [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(27,200)	(5,300)
Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	157,800	142,200
Level 2 [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	157,800	142,200
Level 2 [Member] | Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 2 [Member] | Cash [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 2 [Member] | Net Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 2 [Member] | Net Cash [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 2 [Member] | Accounts Receivable [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 2 [Member] | Accounts Receivable [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 2 [Member] | Accounts Payable [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 2 [Member] | Accounts Payable [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Cash [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Net Cash [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Net Cash [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Accounts Receivable [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Accounts Receivable [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Accounts Payable [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Level 3 [Member] | Accounts Payable [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash Equivalents [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	13,300	16,600
Cash Equivalents [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	13,300	16,600
Cash Equivalents [Member] | Money Markets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	200
Cash Equivalents [Member] | Money Markets [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	200
Cash Equivalents [Member] | Treasury Bills (T bills) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		200
Cash Equivalents [Member] | Treasury Bills (T bills) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		200
Cash Equivalents [Member] | Discounted Notes [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	700	8,800
Cash Equivalents [Member] | Discounted Notes [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	700	8,800
Cash Equivalents [Member] | Short Term Investment Fund (STIF) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12,400	7,600
Cash Equivalents [Member] | Short Term Investment Fund (STIF) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12,400	7,600
Cash Equivalents [Member] | Using NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12,400	7,600
Cash Equivalents [Member] | Using NAV [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12,400	7,600
Cash Equivalents [Member] | Using NAV [Member] | Money Markets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Cash Equivalents [Member] | Using NAV [Member] | Money Markets [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Cash Equivalents [Member] | Using NAV [Member] | Treasury Bills (T bills) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Cash Equivalents [Member] | Using NAV [Member] | Treasury Bills (T bills) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Cash Equivalents [Member] | Using NAV [Member] | Discounted Notes [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash Equivalents [Member] | Using NAV [Member] | Discounted Notes [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash Equivalents [Member] | Using NAV [Member] | Short Term Investment Fund (STIF) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12,400	7,600
Cash Equivalents [Member] | Using NAV [Member] | Short Term Investment Fund (STIF) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12,400	7,600
Cash Equivalents [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash Equivalents [Member] | Level 1 [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash Equivalents [Member] | Level 1 [Member] | Money Markets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Cash Equivalents [Member] | Level 1 [Member] | Money Markets [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Cash Equivalents [Member] | Level 1 [Member] | Treasury Bills (T bills) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Cash Equivalents [Member] | Level 1 [Member] | Treasury Bills (T bills) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Cash Equivalents [Member] | Level 1 [Member] | Discounted Notes [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash Equivalents [Member] | Level 1 [Member] | Discounted Notes [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash Equivalents [Member] | Level 1 [Member] | Short Term Investment Fund (STIF) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash Equivalents [Member] | Level 1 [Member] | Short Term Investment Fund (STIF) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash Equivalents [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	900	9,000
Cash Equivalents [Member] | Level 2 [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	900	9,000
Cash Equivalents [Member] | Level 2 [Member] | Money Markets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	200
Cash Equivalents [Member] | Level 2 [Member] | Money Markets [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	200
Cash Equivalents [Member] | Level 2 [Member] | Treasury Bills (T bills) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		200
Cash Equivalents [Member] | Level 2 [Member] | Treasury Bills (T bills) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		200
Cash Equivalents [Member] | Level 2 [Member] | Discounted Notes [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	700	8,800
Cash Equivalents [Member] | Level 2 [Member] | Discounted Notes [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	700	8,800
Cash Equivalents [Member] | Level 2 [Member] | Short Term Investment Fund (STIF) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash Equivalents [Member] | Level 2 [Member] | Short Term Investment Fund (STIF) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash Equivalents [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash Equivalents [Member] | Level 3 [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash Equivalents [Member] | Level 3 [Member] | Money Markets [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Cash Equivalents [Member] | Level 3 [Member] | Money Markets [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Cash Equivalents [Member] | Level 3 [Member] | Treasury Bills (T bills) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Cash Equivalents [Member] | Level 3 [Member] | Treasury Bills (T bills) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Cash Equivalents [Member] | Level 3 [Member] | Discounted Notes [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash Equivalents [Member] | Level 3 [Member] | Discounted Notes [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash Equivalents [Member] | Level 3 [Member] | Short Term Investment Fund (STIF) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Cash Equivalents [Member] | Level 3 [Member] | Short Term Investment Fund (STIF) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	330,700	319,500
Equity Securities [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	330,700	319,500
Equity Securities [Member] | Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	90,900	98,000
Equity Securities [Member] | Common Stock [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	90,900	98,000
Equity Securities [Member] | American Depository Receipt (ADR) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,700	1,300
Equity Securities [Member] | American Depository Receipt (ADR) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,700	1,300
Equity Securities [Member] | Real Estate Investment Trust (REIT) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,800	2,500
Equity Securities [Member] | Real Estate Investment Trust (REIT) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,800	2,500
Equity Securities [Member] | Preferred Stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		800
Equity Securities [Member] | Preferred Stocks [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		800
Equity Securities [Member] | Commingled Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	53,700	45,600
Equity Securities [Member] | Commingled Fund [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	53,700	45,600
Equity Securities [Member] | Equity Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	175,600	171,300
Equity Securities [Member] | Equity Mutual Funds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	175,600	171,300
Equity Securities [Member] | Using NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	175,600	171,300
Equity Securities [Member] | Using NAV [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	175,600	171,300
Equity Securities [Member] | Using NAV [Member] | Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Using NAV [Member] | Common Stock [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Using NAV [Member] | American Depository Receipt (ADR) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Using NAV [Member] | American Depository Receipt (ADR) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Using NAV [Member] | Real Estate Investment Trust (REIT) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Using NAV [Member] | Real Estate Investment Trust (REIT) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Using NAV [Member] | Preferred Stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Equity Securities [Member] | Using NAV [Member] | Preferred Stocks [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Equity Securities [Member] | Using NAV [Member] | Commingled Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Using NAV [Member] | Commingled Fund [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Using NAV [Member] | Equity Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	175,600	171,300
Equity Securities [Member] | Using NAV [Member] | Equity Mutual Funds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	175,600	171,300
Equity Securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	101,400	102,600
Equity Securities [Member] | Level 1 [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	101,400	102,600
Equity Securities [Member] | Level 1 [Member] | Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	90,900	98,000
Equity Securities [Member] | Level 1 [Member] | Common Stock [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	90,900	98,000
Equity Securities [Member] | Level 1 [Member] | American Depository Receipt (ADR) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,700	1,300
Equity Securities [Member] | Level 1 [Member] | American Depository Receipt (ADR) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,700	1,300
Equity Securities [Member] | Level 1 [Member] | Real Estate Investment Trust (REIT) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,800	2,500
Equity Securities [Member] | Level 1 [Member] | Real Estate Investment Trust (REIT) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	4,800	2,500
Equity Securities [Member] | Level 1 [Member] | Preferred Stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		800
Equity Securities [Member] | Level 1 [Member] | Preferred Stocks [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		800
Equity Securities [Member] | Level 1 [Member] | Commingled Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 1 [Member] | Commingled Fund [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 1 [Member] | Equity Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 1 [Member] | Equity Mutual Funds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	53,700	45,600
Equity Securities [Member] | Level 2 [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	53,700	45,600
Equity Securities [Member] | Level 2 [Member] | Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 2 [Member] | Common Stock [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 2 [Member] | American Depository Receipt (ADR) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 2 [Member] | American Depository Receipt (ADR) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 2 [Member] | Real Estate Investment Trust (REIT) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 2 [Member] | Real Estate Investment Trust (REIT) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 2 [Member] | Preferred Stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Equity Securities [Member] | Level 2 [Member] | Preferred Stocks [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Equity Securities [Member] | Level 2 [Member] | Commingled Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	53,700	45,600
Equity Securities [Member] | Level 2 [Member] | Commingled Fund [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	53,700	45,600
Equity Securities [Member] | Level 2 [Member] | Equity Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 2 [Member] | Equity Mutual Funds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 3 [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 3 [Member] | Common Stock [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 3 [Member] | Common Stock [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 3 [Member] | American Depository Receipt (ADR) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 3 [Member] | American Depository Receipt (ADR) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 3 [Member] | Real Estate Investment Trust (REIT) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 3 [Member] | Real Estate Investment Trust (REIT) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 3 [Member] | Preferred Stocks [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Equity Securities [Member] | Level 3 [Member] | Preferred Stocks [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Equity Securities [Member] | Level 3 [Member] | Commingled Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 3 [Member] | Commingled Fund [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 3 [Member] | Equity Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Equity Securities [Member] | Level 3 [Member] | Equity Mutual Funds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	293,100	315,700
Debt Securities [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	293,100	315,700
Debt Securities [Member] | Commingled Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	117,900	129,200
Debt Securities [Member] | Commingled Fund [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	117,900	129,200
Debt Securities [Member] | Municipal Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,000	6,100
Debt Securities [Member] | Municipal Bonds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,000	6,100
Debt Securities [Member] | Government Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	56,200	47,900
Debt Securities [Member] | Government Bonds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	56,200	47,900
Debt Securities [Member] | Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	32,200	22,000
Debt Securities [Member] | Corporate Bonds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	32,200	22,000
Debt Securities [Member] | Asset Backed Securities (ABS) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	300	300
Debt Securities [Member] | Asset Backed Securities (ABS) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	300	300
Debt Securities [Member] | Mortgage Back Securities (MBS) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8,700	9,600
Debt Securities [Member] | Mortgage Back Securities (MBS) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8,700	9,600
Debt Securities [Member] | CMO [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,500	2,000
Debt Securities [Member] | CMO [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,500	2,000
Debt Securities [Member] | Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	71,300	98,600
Debt Securities [Member] | Mutual Funds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	71,300	98,600
Debt Securities [Member] | Using NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	189,200	227,800
Debt Securities [Member] | Using NAV [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	189,200	227,800
Debt Securities [Member] | Using NAV [Member] | Commingled Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	117,900	129,200
Debt Securities [Member] | Using NAV [Member] | Commingled Fund [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	117,900	129,200
Debt Securities [Member] | Using NAV [Member] | Municipal Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Using NAV [Member] | Municipal Bonds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Using NAV [Member] | Government Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Using NAV [Member] | Government Bonds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Using NAV [Member] | Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Using NAV [Member] | Corporate Bonds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Using NAV [Member] | Asset Backed Securities (ABS) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Using NAV [Member] | Asset Backed Securities (ABS) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Using NAV [Member] | Mortgage Back Securities (MBS) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Using NAV [Member] | Mortgage Back Securities (MBS) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Using NAV [Member] | CMO [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Using NAV [Member] | CMO [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Using NAV [Member] | Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	71,300	98,600
Debt Securities [Member] | Using NAV [Member] | Mutual Funds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	71,300	98,600
Debt Securities [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 1 [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 1 [Member] | Commingled Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 1 [Member] | Commingled Fund [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 1 [Member] | Municipal Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 1 [Member] | Municipal Bonds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 1 [Member] | Government Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 1 [Member] | Government Bonds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 1 [Member] | Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 1 [Member] | Corporate Bonds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 1 [Member] | Asset Backed Securities (ABS) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 1 [Member] | Asset Backed Securities (ABS) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 1 [Member] | Mortgage Back Securities (MBS) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 1 [Member] | Mortgage Back Securities (MBS) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 1 [Member] | CMO [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 1 [Member] | CMO [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 1 [Member] | Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 1 [Member] | Mutual Funds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	103,900	87,900
Debt Securities [Member] | Level 2 [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	103,900	87,900
Debt Securities [Member] | Level 2 [Member] | Commingled Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 2 [Member] | Commingled Fund [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 2 [Member] | Municipal Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,000	6,100
Debt Securities [Member] | Level 2 [Member] | Municipal Bonds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,000	6,100
Debt Securities [Member] | Level 2 [Member] | Government Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	56,200	47,900
Debt Securities [Member] | Level 2 [Member] | Government Bonds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	56,200	47,900
Debt Securities [Member] | Level 2 [Member] | Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	32,200	22,000
Debt Securities [Member] | Level 2 [Member] | Corporate Bonds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	32,200	22,000
Debt Securities [Member] | Level 2 [Member] | Asset Backed Securities (ABS) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	300	300
Debt Securities [Member] | Level 2 [Member] | Asset Backed Securities (ABS) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	300	300
Debt Securities [Member] | Level 2 [Member] | Mortgage Back Securities (MBS) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8,700	9,600
Debt Securities [Member] | Level 2 [Member] | Mortgage Back Securities (MBS) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8,700	9,600
Debt Securities [Member] | Level 2 [Member] | CMO [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,500	2,000
Debt Securities [Member] | Level 2 [Member] | CMO [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,500	2,000
Debt Securities [Member] | Level 2 [Member] | Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 2 [Member] | Mutual Funds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 3 [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 3 [Member] | Commingled Fund [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 3 [Member] | Commingled Fund [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 3 [Member] | Municipal Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 3 [Member] | Municipal Bonds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 3 [Member] | Government Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 3 [Member] | Government Bonds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 3 [Member] | Corporate Bonds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 3 [Member] | Corporate Bonds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 3 [Member] | Asset Backed Securities (ABS) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 3 [Member] | Asset Backed Securities (ABS) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 3 [Member] | Mortgage Back Securities (MBS) [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 3 [Member] | Mortgage Back Securities (MBS) [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 3 [Member] | CMO [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 3 [Member] | CMO [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 3 [Member] | Mutual Funds [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Debt Securities [Member] | Level 3 [Member] | Mutual Funds [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Derivative [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(800)	(400)
Derivative [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(800)	(400)
Derivative [Member] | Swaps [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(900)
Derivative [Member] | Swaps [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(900)
Derivative [Member] | Purchased Options [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,100	700
Derivative [Member] | Purchased Options [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,100	700
Derivative [Member] | Written Options [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(1,000)	(800)
Derivative [Member] | Written Options [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(1,000)	(800)
Derivative [Member] | Short [Member] | Futures [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		(300)
Derivative [Member] | Short [Member] | Futures [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		(300)
Derivative [Member] | Using NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Derivative [Member] | Using NAV [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Derivative [Member] | Using NAV [Member] | Swaps [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Derivative [Member] | Using NAV [Member] | Swaps [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Derivative [Member] | Using NAV [Member] | Purchased Options [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Derivative [Member] | Using NAV [Member] | Purchased Options [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Derivative [Member] | Using NAV [Member] | Written Options [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Derivative [Member] | Using NAV [Member] | Written Options [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Derivative [Member] | Using NAV [Member] | Short [Member] | Futures [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Derivative [Member] | Using NAV [Member] | Short [Member] | Futures [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Derivative [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Derivative [Member] | Level 1 [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Derivative [Member] | Level 1 [Member] | Swaps [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Derivative [Member] | Level 1 [Member] | Swaps [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Derivative [Member] | Level 1 [Member] | Purchased Options [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Derivative [Member] | Level 1 [Member] | Purchased Options [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Derivative [Member] | Level 1 [Member] | Written Options [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Derivative [Member] | Level 1 [Member] | Written Options [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Derivative [Member] | Level 1 [Member] | Short [Member] | Futures [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Derivative [Member] | Level 1 [Member] | Short [Member] | Futures [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Derivative [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(800)	(400)
Derivative [Member] | Level 2 [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(800)	(400)
Derivative [Member] | Level 2 [Member] | Swaps [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(900)
Derivative [Member] | Level 2 [Member] | Swaps [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(900)
Derivative [Member] | Level 2 [Member] | Purchased Options [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,100	700
Derivative [Member] | Level 2 [Member] | Purchased Options [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,100	700
Derivative [Member] | Level 2 [Member] | Written Options [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(1,000)	(800)
Derivative [Member] | Level 2 [Member] | Written Options [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	(1,000)	(800)
Derivative [Member] | Level 2 [Member] | Short [Member] | Futures [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		(300)
Derivative [Member] | Level 2 [Member] | Short [Member] | Futures [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		(300)
Derivative [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Derivative [Member] | Level 3 [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Derivative [Member] | Level 3 [Member] | Swaps [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Derivative [Member] | Level 3 [Member] | Swaps [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0
Derivative [Member] | Level 3 [Member] | Purchased Options [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Derivative [Member] | Level 3 [Member] | Purchased Options [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Derivative [Member] | Level 3 [Member] | Written Options [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Derivative [Member] | Level 3 [Member] | Written Options [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Derivative [Member] | Level 3 [Member] | Short [Member] | Futures [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Derivative [Member] | Level 3 [Member] | Short [Member] | Futures [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets		0
Miscellaneous [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	100	100
Miscellaneous [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	100	100
Miscellaneous [Member] | Using NAV [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Miscellaneous [Member] | Using NAV [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Miscellaneous [Member] | Level 1 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Miscellaneous [Member] | Level 1 [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Miscellaneous [Member] | Level 2 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	100	100
Miscellaneous [Member] | Level 2 [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	100	100
Miscellaneous [Member] | Level 3 [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Miscellaneous [Member] | Level 3 [Member] | Tampa Electric Company [Member]
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 0	$ 0