Income Taxes (Tables)

12 Months Ended

Dec. 31, 2015

Income Tax Provision (Benefit) Charged to Continuing Operations, Accumulated Other Comprehensive Income (Loss) or Additional Paid-In Capital [Abstract]

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

Income tax expense for continuing operations consisted of the following:

	Year Ended December 31,
(dollars in millions)	2015			2014			2013
Current:
Federal	$	9.2		$	9.3		$	—
State and local	1.7			1.9			—
Total current	10.9			11.2			—
Investment tax credits	(0.2		)	(0.2		)	(0.2		)
Deferred:
Federal	149.4			69.6			(18.5		)
State and local	5.2			1.9			(4.0		)
Foreign	—			—			0.3
Total deferred	154.6			71.5			(22.2		)
Valuation allowance	(5.5		)	(1.1		)	14.1
Total	$	159.8		$	81.4		$	(8.3	)

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

The following is a reconciliation of the statutory federal income tax rate with the effective tax rate for each year:

	Year Ended December 31,
	2015		2014		2013
U.S. federal statutory rate	35.0	%	35.0	%	35.0	%
State and local income taxes, net of federal income tax	0.7		0.8		1.5
Change in valuation allowance, net of federal income tax	(0.8	)	(2.0	)	(12.4	)
State net operating loss adjustments	0.3		1.9		2.1
Nondeductible interest expense	—		2.7		(8.9	)
Unrecognized tax benefit changes	0.2		1.4		(1.7	)
Nondeductible compensation	0.1		0.7		(2.0	)
Foreign	—		—		(0.5	)
Other differences, net	—		0.4		(1.7	)
Effective tax rate	35.5	%	40.9	%	11.4	%

Schedule of income tax provision charged to continuing operations, accumulated other comprehensive income (loss) or additional paid-in capital [Table Text Block]

The income tax (benefit) provision was charged to continuing operations, discontinued operations, accumulated other comprehensive income or additional paid-in capital as follows:

	Year Ended December 31,
(dollars in millions)	2015			2014			2013
Income tax (benefit) provision related to:
Continuing operations	$	159.8		$	81.4		$	(8.3	)
Discontinued operations	34.8			(24.0		)	5.8
Accumulated other comprehensive income (loss)	2.0			(22.4		)	42.1
Excess tax benefits on stock option exercises	(0.1		)	(0.1		)	(0.5		)

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

The components of our deferred tax assets and liabilities were as follows:

	December 31,
(dollars in millions)	2015			2014
Deferred tax assets:
Net operating loss carryforwards	$	142.0		$	286.5
Pension and postretirement benefits	89.1			95.5
Investment in CyrusOne	68.9			64.5
Deferred gain on sale of wireless spectrum licenses	—			42.2
AMT Credit Carryforward	32.7			24.7
Other	43.8			47.4
Total deferred tax assets	376.5			560.8
Valuation allowance	(58.4		)	(64.4		)
Total deferred tax assets, net of valuation allowance	$	318.1		$	496.4
Deferred tax liabilities:
Property, plant and equipment	$	134.9		$	121.9
Other	0.3			4.9
Total deferred tax liabilities	135.2			126.8
Net deferred tax assets	$	182.9		$	369.6

Schedule of Unrecognized Tax Benefits Roll Forward [Table Text Block]

A reconciliation of the unrecognized tax benefits is as follows:

	Year Ended December 31,
(dollars in millions)	2015		2014		2013
Balance, beginning of year	$	27.1	$	24.1	$	22.8
Change in tax positions for the current year	0.5		3.0		1.3
Change in tax positions for prior years	—		—		—
Balance, end of year	$	27.6	$	27.1	$	24.1