Income Taxes (Tables)

12 Months Ended

Dec. 31, 2013

Schedule of Components of Income Tax Expense (Benefit) [Table Text Block]

Details of income tax expenses and deferred income taxes from continuing operations are provided in the following tables. The components of income tax expenses were as follows:



	Year Ended December 31,
	2013			2012			2011
	(in millions)
Federal income tax expense (benefit)
Current	$	47.9		$	33.7		$	(5.3	)
Deferred	69.1			36.5			153.0
State income tax expense (benefit)
Current	5.7			0.7			2.9
Deferred	(2.9		)	(4.4		)	3.8
Total income tax expense	$	119.8		$	66.5		$	154.4

Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]

The difference between the statutory federal income tax rate and the Company's effective income tax rate is explained as follows:



	Year Ended December 31,
	2013		2012		2011
Federal income taxes statutory rate	35.0	%	35.0	%	35.0	%
Increase (decrease) in rate as a result of:
State income taxes, net of federal income tax benefit	0.6	%	(1.2	)%	1.0	%
Penalties	0.2	%	(0.6	)%	—	%
Return to provision adjustment	(0.2	)%	0.4	%	1.3	%
Noncontrolling interest	(1.4	)%	(0.7	)%	(0.3	)%
Book impairment of goodwill	7.2	%	—	%	—	%
Other	(0.3	)%	0.6	%	(0.7	)%
Effective income tax rate	41.1	%	33.5	%	36.3	%

Schedule of Deferred Tax Assets and Liabilities [Table Text Block]



	December 31,
	2013		2012
	(in millions)
Deferred tax liabilities
Property, plant and equipment	$	1,651.1	$	1,606.6
Commodity price and interest rate derivatives	—		69.4
Total deferred tax liabilities	1,651.1		1,676
Deferred tax assets
Commodity price and interest rate derivatives	9.7		—
Net operating loss and tax credit carryforwards	54.6		65.6
Employee benefits and compensation costs	36.1		47.7
Accrued litigation loss contingency	0.8		42.8
Bonus and vacation accrual	10.6		11.8
Other	9.3		9.6
Total deferred tax assets	121.1		177.5
Net deferred income tax liability	$	1,530.0	$	1,498.5
Balance sheet classification
Deferred income tax asset - current	$	30.6	$	—
Deferred income tax liability -current	—		$	5.0
Deferred income tax liability - non-current	1,560.6		1,493.5
Net deferred income tax liability	$	1,530.0	$	1,498.5

Summary of Operating Loss Carryforwards [Table Text Block]

The amounts and expiration dates of net operating loss and tax credit carryforwards at December 31, 2013 are as follows:



	Expiration Dates	Amounts
		(in millions)
State net operating loss and tax credit carryforwards	2014-2032	$	26.5
U.S. alternative minimum tax credit	Indefinite	28.1
Total		$	54.6