Accounts Receivable from one customer greater than 10%, percentage

No definition available.

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- Definition

The average life expectancy of retirees, in years, for the Company's management postretirement plan over which excess unrecognized actuarial gains or losses are amortized.

+ References

No definition available.

+ Details

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- Definition

The lower range, in years, of customer contracts over which revenue for maintenance services on telephony equipment is deferred and recognized ratably.

+ References

No definition available.

+ Details

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Period Type:	duration

- Definition

The upper range, in years, of customer contracts over which revenue for maintenance services on telephony equipment is deferred and recognized ratably.

+ References

No definition available.

+ Details

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- Details

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- Definition

The number of operating partnership units of CyrusOne LP sold during the period.

+ References

No definition available.

+ Details

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Balance Type:	na
Period Type:	duration

- Definition

The number of partnership units of CyrusOne LP, the operating partnership, owned by the Company. These partnership units are exchangeable into shares of common stock of CyrusOne Inc. on a one-for-one basis.

+ References

No definition available.

+ Details

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- Definition

The Company's ownership interest, in shares, in the common stock of CyrusOne Inc., the publicly-traded real estate investment trust entity, following the completion of the initial public offering on January 24, 2013.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

The Company's ownership interest in CyrusOne Inc., the publicly-traded real estate investment trust entity, following the completion of the initial public offering on January 24, 2013.

+ References

No definition available.

+ Details

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- Definition

The company's percentage ownership interest in CyrusOne LP, the operating partnership, after the initial public offering of CyrusOne Inc. on January 24, 2013.

+ References

No definition available.

+ Details

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- Definition

The value of certain leases and other assets to be transferred to the acquiring company in conjunction with the sale of the wireless spectrum licenses.

+ References

No definition available.

+ Details

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Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

The lower range, in years, of the remaining service life of active employees for the pension and bargained postretirement plans over which excess unrecognized actuarial gains or losses are amortized.

+ References

No definition available.

+ Details

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Period Type:	instant

- Definition

The number of customers whose accounts receivable balance exceeds 10% of total accounts receivable.

+ References

No definition available.

+ Details

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Data Type:	xbrli:integerItemType
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Period Type:	instant

- Definition

The percentage of the Company's revenue generated by foreign subsidiaries.

+ References

No definition available.

+ Details

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Data Type:	num:percentItemType
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Period Type:	duration

- Definition

The amount of federal regulatory taxes recorded as cost of services that are related to certain revenue producing transactions.

+ References

No definition available.

+ Details

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Namespace Prefix:	cbb_
Data Type:	xbrli:monetaryItemType
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- Definition

The amount of federal regulatory taxes recorded as revenue that are derived from certain revenue producing transactions.

+ References

No definition available.

+ Details

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Balance Type:	debit
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- Definition

Revenue from one customer greater than 10%, percentage

+ References

No definition available.

+ Details

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- Definition

The per-unit sales price received by the Company for each operating partnership unit of CyrusOne LP sold during the period.

+ References

No definition available.

+ Details

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Data Type:	num:perShareItemType
Balance Type:	na
Period Type:	duration

- Definition

The Company's total combined direct and indirect owership interests in CyrusOne Inc., the REIT entity, and CyrusOne LP, the operating partnership.

+ References

No definition available.

+ Details

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- Definition

The number of days that customers generally have to pay outstanding accounts receivable balances. This represents the upper end of the range for standard payment terms.

+ References

No definition available.

+ Details

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- Definition

The number of days that customers generally have to pay outstanding accounts receivable balances. This represents the low end of the range for standard payment terms.

+ References

No definition available.

+ Details

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- Definition

The upper range, in years, of the remaining service life of active employees for the pension and bargained postretirement plans over which excess unrecognized actuarial gains or losses are amortized.

+ References

No definition available.

+ Details

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- Definition

Amount charged to advertising expense for the period, which are expenses incurred with the objective of increasing revenue for a specified brand, product or product line.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 720

-SubTopic 35

-Section 50

-Paragraph 1

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Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- Definition

Amount, after adjustment, of cost-method investment. Adjustments include, but are not limited to, dividends received in excess of earnings after date of investment that are considered a return of investment and other than temporary impairments.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 210

-SubTopic 10

-Section S99

-Paragraph 1

-Subparagraph (SX 210.5-02.12)

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 325

-SubTopic 20

-Section 50

-Paragraph 1

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-Name Accounting Standards Codification

-Topic 325

-SubTopic 20

-Section 35

-Paragraph 2

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- Definition

Amount of gain on the sale of property that does not qualify for gain recognition as of the balance sheet date.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 605

-SubTopic 40

-Section S99

-Paragraph 1

-Subparagraph (SAB TOPIC 5.U.Q2)

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- Definition

Amount of increase (decrease) of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 350

-SubTopic 30

-Section 50

-Paragraph 2

-Subparagraph (b)

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Balance Type:	na
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- Definition

Amount of rent expense incurred for leased assets, including but not limited to, furniture and equipment, that is not directly or indirectly associated with the manufacture, sale or creation of a product or product line.

+ References

No definition available.

+ Details

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Balance Type:	debit
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- Definition

Number of operating segments. An operating segment is a component of an enterprise: (a) that engages in business activities from which it may earn revenues and incur expenses (including revenues and expenses relating to transactions with other components of the same enterprise), (b) whose operating results are regularly reviewed by the enterprise's chief operating decision maker to make decisions about resources to be allocated to the segment and assess its performance, and (c) for which discrete financial information is available. An operating segment may engage in business activities for which it has yet to earn revenues, for example, start-up operations may be operating segments before earning revenues.

+ References

No definition available.

+ Details

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- Definition

The cash outflow associated with the purchase of or advances to an equity method investments, which are investments in joint ventures and entities in which the entity has an equity ownership interest normally of 20 to 50 percent and exercises significant influence.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 13

-Subparagraph (b)

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- Definition

Carrying amount as of the balance sheet date of expenditures made in advance of when the economic benefit of the cost will be realized, and which will be expensed in future periods with the passage of time or when a triggering event occurs.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 942

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.9-03.10)

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-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 03

-Paragraph 10

-Article 9

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-Publisher FASB

-Name Accounting Standards Codification

-Topic 944

-SubTopic 210

-Section S99

-Paragraph 1

-Subparagraph (SX 210.7-03.10)

-URI http://asc.fasb.org/extlink&oid=6879938&loc=d3e572229-122910

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Balance Type:	debit
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- Definition

Cash dividends or other distributions received from unconsolidated subsidiaries, certain corporate joint ventures, and certain noncontrolled corporations that are returns of capital. Excludes dividends or distributions from equity method investments classified as operating activities.

+ References

No definition available.

+ Details

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- Definition

The cash inflow from disposal of asset without physical form usually arising from contractual or other legal rights, excluding goodwill.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Glossary Investing Activities

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-Name Accounting Standards Codification

-Topic 230

-SubTopic 10

-Section 45

-Paragraph 12

-Subparagraph (c)

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- Definition

Amount received for services rendered and products shipped, but not yet billed, for non-contractual agreements due within one year or the normal operating cycle, if longer.

+ References

No definition available.

+ Details

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Description of Business and Accounting Policies Description of Business and Accounting Policies (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended		12 Months Ended
	Jun. 30, 2014	Mar. 31, 2013	Dec. 31, 2015	Dec. 31, 2014 D	Dec. 31, 2013	Dec. 31, 2012	Sep. 30, 2014	Jan. 24, 2013
Description of accounting policies [Line Items]
Percent of Revenue from Foreign Subsidiaries				1.00%
Number of Operating Segments		4us-gaap_NumberOfOperatingSegments		3us-gaap_NumberOfOperatingSegments
Investment owned in CyrusOne Inc., Balance, Shares				1.9				1.9
Investment owned in CyrusOne Inc., Percentage, Common Stock								8.60%
Investment in CyrusOne LP, Balance, Partnership Units				26.6				42.6
Investment owned in CyrusOne LP, Percentage, Partnership Units								66.00%
Total ownership interests in CyrusOne, Percentage				44.00%	68.00%			69.00%
Equity Method Investment Sold, Partnership Units	16.0
Sale of Partnership Units, Price Per Unit	$ 22.26cbb_SaleofPartnershipUnitsPricePerUnit
Proceeds from sale of Wireless spectrum licenses	$ 194.4			$ 194.4	$ 0	$ 0
Indefinite-lived Intangible Assets, Period Increase (Decrease)	88.2
Prepaid Expense				3.2			6.4
Deferred gain in wireless spectrum licenses				112.6us-gaap_DeferredGainOnSaleOfProperty	0us-gaap_DeferredGainOnSaleOfProperty
Operating Leases, Rent Expense				14.0us-gaap_LeaseAndRentalExpense	13.4us-gaap_LeaseAndRentalExpense	19.3us-gaap_LeaseAndRentalExpense
Liabilities and Other Assets transferred in Sale of Business, Affiliate and Productive Assets			25	25
Trade Receivables Due From Customers, Range, Minimum				21
Trade Receivables Due from Customers, Range, Maximum				90
Number of customers, exceeds 10% of total accounts receivable				1
Accounts Receivable from one customer greater than 10%, percentage				26.00%	19.00%
Revenue from one customer greater than 10%, percentage				14.00%
Unbilled Receivables, Current				15.6us-gaap_UnbilledReceivablesCurrent	23.2us-gaap_UnbilledReceivablesCurrent
Dividends received from CyrusOne				28.4	21.3	0
Payments to Acquire Equity Method Investments				5.5
Cost Method Investments				2.9us-gaap_CostMethodInvestments	2.5us-gaap_CostMethodInvestments
Customer Contract, Lower Range, in Years				1cbb_CustomerContractLowerRangeinYears
Customer Contract, Upper Range, in Years				3cbb_CustomerContractUpperRangeinYears
Advertising Expense				8.9us-gaap_AdvertisingExpense	12.2us-gaap_AdvertisingExpense	16.6us-gaap_AdvertisingExpense
Regulatory Taxes Included in Revenue				17.9cbb_RegulatoryTaxesIncludedInRevenue	18.9cbb_RegulatoryTaxesIncludedInRevenue	22.2cbb_RegulatoryTaxesIncludedInRevenue
Regulatory Taxes Included in Expense				$ 19.6cbb_RegulatoryTaxesIncludedInExpense	$ 19.2cbb_RegulatoryTaxesIncludedInExpense	$ 24.4cbb_RegulatoryTaxesIncludedInExpense
Lower range, in years, of remaining service life of active employees				10
Upper range, in years, of remaining service life of active employees				14
Other Postretirement Benefit Plans, Defined Benefit [Member]
Description of accounting policies [Line Items]
Average life expectancy of retirees, in years				16