Discontinued Operations (Tables) - Discontinued Operations [Member]

12 Months Ended

Dec. 31, 2017

Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]

Disposal Groups, Including Discontinued Operations [Table Text Block]

Wireless financial results for the twelve months ended December 31, 2017, 2016 and 2015 reported as "Income from discontinued operations, net of tax" on the Consolidated Statements of Operations are as follows:

	Twelve Months Ended
	December 31,
(dollars in millions)	2017		2016			2015
Revenue	$	—	$	—		$	4.4
Costs and expenses
Cost of products and services	—		—			12.0
Selling, general and administrative	—		—			2.2
Depreciation and amortization expense	—		—			28.6
Restructuring charges	—		—			3.3
Gain on sale or disposal of assets	—		—			(0.4		)
Amortization of deferred gain	—		—			(6.5		)
Total operating costs and expenses	—		—			39.2
Operating Loss	—		—			(34.8		)
Interest income	—		—			(1.7		)
Other income	—		(0.3		)	(2.3		)
Gain on transfer of tower lease obligations and other assets	—		—			15.9
Gain on sale of wireless spectrum licenses	—		—			112.6
Income before income taxes	—		0.3			97.7
Income tax expense	—		—			34.8
Income from discontinued operations, net of tax	$	—	$	0.3		$	62.9

Condensed Cash Flow Statement [Table Text Block]

Following is selected operating and financing cash flow activity from discontinued operations included in Consolidated Statements of Cash Flows:

	Twelve Months Ended
	December 31,
(dollars in millions)	2017		2016			2015
Depreciation and amortization	$	—	$	—		$	28.6
Gain on sale of assets	—		—			(0.4		)
Deferred gain on sale of spectrum licenses	—		—			(112.6		)
Amortization of deferred gain on sale of towers	—		—			(6.5		)
Gain on transfer of tower lease obligations and other assets	—		—			(15.9		)
Non-cash spectrum lease	—		—			3.2
Restructuring payments	—		(4.4		)	(14.5		)
Repayment of debt	—		—			(0.3		)