INCOME TAXES (Tables)

12 Months Ended

Dec. 31, 2013

Income Tax Disclosure [Abstract]

Schedule of principal components of deferred income tax assets and liabilities recognized in the balance sheets

(Millions)	2013			2012
Deferred income tax assets
Tax credit carryforwards	$	113.5		$	105.1
Price risk management	13.0			59.6
Other	98.5			76.5
Total deferred income tax assets	$	225.0		$	241.2
Valuation allowance	(8.2		)	(7.2		)
Net deferred income tax assets	$	216.8		$	234.0
Deferred income tax liabilities
Plant-related	$	1,373.8		$	1,215.7
Employee benefits	79.6			49.1
Regulatory deferrals	78.8			60.8
Other	43.5			47.9
Total deferred income tax liabilities	$	1,575.7		$	1,373.5
Total net deferred income tax liabilities	$	1,358.9		$	1,139.5
Balance sheet presentation
Current deferred income tax assets	$	31.4		$	64.3
Long-term deferred income tax liabilities	1,390.3			1,203.8
Net deferred income tax liabilities	$	1,358.9		$	1,139.5

Schedule of components of foreign and domestic income included in income before taxes

Income before taxes includes the following components of foreign and domestic income:

	For the Years Ended December 31
(Millions)	2013		2012			2011
Domestic	$	560.8	$	443.9		$	363.4
Foreign	—		(0.1		)	(0.1		)
Total income before taxes	$	560.8	$	443.8		$	363.3

Schedule of components of the provision for income tax expense

The components of the provision for income taxes were as follows:

(Millions)	2013			2012			2011
Current provision
Federal	$	7.8		$	3.5		$	(44.2	)
State	5.9			0.4			6.0
Foreign	0.1			(0.1		)	(0.2		)
Total current provision	13.8			3.8			(38.4		)
Deferred provision
Federal	174.8			128.3			158.7
State	14.9			20.1			14.6
Foreign	—			—			0.1
Total deferred provision	189.7			148.4			173.4
Investment tax credits, net	8.4			5.2			(1.1		)
Penalties	(0.1		)	(0.3		)	0.7
Unrecognized tax benefits	0.4			(3.0		)	0.9
Interest	(1.4		)	(4.3		)	(2.2		)
Total provision for income taxes related to continuing operations	210.8			149.8			133.3
Total provision for income taxes related to discontinued operations	(6.9		)	(9.3		)	1.1
Total	$	203.9		$	140.5		$	134.4

Reconciliation of federal income taxes to the provision for income taxes reported in the income statement

The following table presents a reconciliation of the difference between the effective tax rate and the amount computed by applying the statutory federal tax rate to income before taxes.

	2013					2012					2011
(Millions, except for percentages)	Rate		Amount			Rate		Amount			Rate		Amount
Statutory federal income tax	35.0	%	$	196.3		35.0	%	$	155.4		35.0	%	$	127.2
State income taxes, net	3.9		21.8			4.8		21.1			5.3		19.1
Federal tax credits	(0.1	)	(0.5		)	(1.7	)	(7.6		)	(2.0	)	(7.1		)
Benefits and compensation	(0.7	)	(4.2		)	(2.1	)	(9.4		)	(2.3	)	(8.4		)
Other differences, net	(0.5	)	(2.6		)	(2.2	)	(9.7		)	0.7		2.5
Effective income tax	37.6	%	$	210.8		33.8	%	$	149.8		36.7	%	$	133.3

Reconciliation of the beginning and ending amount of unrecognized tax benefits

A reconciliation of the beginning and ending amount of unrecognized tax benefits is as follows:

(Millions)	2013			2012			2011
Balance at January 1	$	11.3		$	22.4		$	30.4
Increase related to tax positions taken in prior years	2.2			0.9			3.1
Decrease related to tax positions taken in prior years	(8.7		)	(6.7		)	(1.6		)
Increase related to tax positions taken in current year	0.3			0.6			0.9
Decrease related to settlements	(1.5		)	(5.7		)	(9.4		)
Decrease related to lapse of statutes	—			(0.2		)	(1.0		)
Balance at December 31	$	3.6		$	11.3		$	22.4

Schedule of the earliest open tax years that were subject to examination by state taxing authorities by major operating jurisdictions

As of December 31, 2013, we were subject to examination by state or local tax authorities for the 2008 through 2012 tax years in our major state operating jurisdictions as follows:

State	Year
Illinois	2008
Michigan	2008
Minnesota	2011
Wisconsin	2009