Income Taxes (Tables)

12 Months Ended

Dec. 31, 2016

Income Tax Disclosure [Abstract]

Schedule of Income Tax Expense

Income tax expense consists of the following components:

(millions)
For the year ended December 31,	2016		2015		2014
Current income taxes
Federal	$	52.7	$	38.2	$	54.8
State		11.8		8.4		8.9
Deferred income taxes
Federal		75.7		102.9		79.0
State		11.0		14.5		13.5
Investment tax credits, net of amortization		1.0		1.5		(0.3	)
Total income tax expense	$	152.2	$	165.5	$	155.9

Schedule of Income Taxes Calculated on Income before Income Taxes and Provision for Income Taxes

For the three years presented, the overall effective tax rate differs from the 35% U.S. federal statutory rate as presented below:

(millions)
For the year ended December 31,	2016			2015			2014
Income before provision for income taxes	$	437.9		$	441.8		$	416.2
Federal statutory income tax rates		35	%		35	%		35	%
Income taxes, at statutory income tax rate		153.3			154.6			145.7
Increase (decrease) due to
State income tax, net of federal income tax		14.8			14.8			14.5
AFUDC-equity		(8.4	)		(6.0	)		(3.7	)
Tax credits		(6.8	)		0.0			0.0
Other		(0.7	)		2.1			(0.6	)
Total income tax expense on consolidated statements of income	$	152.2		$	165.5		$	155.9
Income tax expense as a percent of income from continuing operations,    before income taxes		34.8	%		37.5	%		37.5	%

Schedule of Deferred Tax Assets and Liabilities

The principal components of TEC’s deferred tax assets and liabilities recognized in the balance sheet are as follows:

(millions)
As of December 31,	2016		2015
Deferred tax liabilities (1)
Property related	$	1,549.1	$	1,431.9
Pension and postretirement benefits		105.0		92.0
Pension		69.2		71.1
Total deferred tax liabilities		1,723.3		1,595.0
Deferred tax assets (1)
Loss and credit carryforwards (2)		91.3		80.0
Medical benefits		46.9		47.7
Insurance reserves		27.3		27.6
Pension and postretirement benefits		105.0		92.0
Capitalized energy conservation assistance costs		22.9		21.4
Other		23.3		17.5
Total deferred tax assets		316.7		286.2
Total deferred tax liability, net	$	1,406.6	$	1,308.8

(1) Certain property related assets and liabilities have been netted.

(2) Deferred tax assets for net operating loss and tax credit carryforwards have been reduced by unrecognized tax benefits of $6.8 million.

Schedule of Unrecognized Tax Benefits

The following table provides details of the change in unrecognized tax benefits as follows:

(millions)	2016		2015		2014
Balance at January 1,	$	0.0	$	0.0	$	0.0
Increases due to tax positions related to current year		6.8		0.0		0.0
Balance at December 31	$	6.8	$	0.0	$	0.0