Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 805
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147479907/805-20-50-5

+ Details

Name:	us-gaap_BusinessAcquisitionLineItems
Namespace Prefix:	us-gaap_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetUsefulLife
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

Amount before amortization of assets, excluding financial assets and goodwill, lacking physical substance with a finite life.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 928
-SubTopic 340
-Name Accounting Standards Codification
-Section 50
-Paragraph 1
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147483147/928-340-50-1

Reference 2: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 350
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (a)(1)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482665/350-30-50-2

+ Details

Name:	us-gaap_FiniteLivedIntangibleAssetsGross
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

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

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Topic 350
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 2
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147482665/350-30-50-2

+ Details

Name:	us-gaap_IndefiniteLivedIntangibleAssetsExcludingGoodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Amount before accumulated amortization of intangible assets, excluding goodwill.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 210
-SubTopic 10
-Name Accounting Standards Codification
-Section S99
-Paragraph 1
-Subparagraph (SX 210.5-02(15))
-Publisher FASB
-URI https://asc.fasb.org//1943274/2147480566/210-10-S99-1

+ Details

Name:	us-gaap_IntangibleAssetsGrossExcludingGoodwill
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Details

Name:	us-gaap_BusinessAcquisitionAxis=ck0000716133_CincinnatiBellIncorporationMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_BusinessAcquisitionAxis=ck0000716133_AgileIwgHoldingsLlcMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_CustomerRelationshipsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_TradeNamesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MinimumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	srt_RangeAxis=srt_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=us-gaap_TechnologyBasedIntangibleAssetsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_FiniteLivedIntangibleAssetsByMajorClassAxis=ck0000716133_FCCLicensesAndSpectrumUsageRightsMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Mergers and Acquisitions - Fair Values of Identifiable Intangible Assets Acquired (Details) - USD ($) $ in Millions	Dec. 31, 2023	Dec. 31, 2022	May 02, 2022	Sep. 07, 2021
Business Acquisition [Line Items]
Fair Value	$ 979.4	$ 977.6
Fair Value	993.3	991.3
Cincinnati Bell Inc. [Member]
Business Acquisition [Line Items]
Fair Value				$ 969.6
Agile IWG Holdings, LLC [Member]
Business Acquisition [Line Items]
Fair Value			$ 19.4
Fair Value			19.4
Customer Relationships [Member]
Business Acquisition [Line Items]
Fair Value	$ 863.5	862.1
Useful Lives	15 years
Customer Relationships [Member] \| Cincinnati Bell Inc. [Member]
Business Acquisition [Line Items]
Fair Value				$ 850.0
Useful Lives				15 years
Customer Relationships [Member] \| Agile IWG Holdings, LLC [Member]
Business Acquisition [Line Items]
Fair Value			$ 16.0
Useful Lives			15 years
Trade Names [Member]
Business Acquisition [Line Items]
Fair Value	$ 109.8	109.5
Trade Names [Member] \| Minimum [Member]
Business Acquisition [Line Items]
Useful Lives	3 years
Trade Names [Member] \| Maximum [Member]
Business Acquisition [Line Items]
Useful Lives	10 years
Trade Names [Member] \| Cincinnati Bell Inc. [Member]
Business Acquisition [Line Items]
Fair Value				$ 108.0
Trade Names [Member] \| Cincinnati Bell Inc. [Member] \| Minimum [Member]
Business Acquisition [Line Items]
Useful Lives				3 years
Trade Names [Member] \| Cincinnati Bell Inc. [Member] \| Maximum [Member]
Business Acquisition [Line Items]
Useful Lives				10 years
Trade Names [Member] \| Agile IWG Holdings, LLC [Member]
Business Acquisition [Line Items]
Fair Value			$ 2.3
Useful Lives			10 years
Technology [Member]
Business Acquisition [Line Items]
Fair Value	$ 6.1	$ 6.0
Useful Lives	7 years
Technology [Member] \| Cincinnati Bell Inc. [Member]
Business Acquisition [Line Items]
Fair Value				$ 5.0
Useful Lives				7 years
Technology [Member] \| Agile IWG Holdings, LLC [Member]
Business Acquisition [Line Items]
Fair Value			$ 1.1
Useful Lives			7 years
FCC Licenses and Spectrum Usage Rights [Member] \| Cincinnati Bell Inc. [Member]
Business Acquisition [Line Items]
Fair Value				$ 6.6