Additional future payments on finance leases not yet commenced.

No definition available.

Name:	ck0000716133_AdditionalFuturePaymentsOnFinanceLeasesNotYetCommenced
Namespace Prefix:	ck0000716133_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Additional future payments on operating leases not yet commenced.

+ References

No definition available.

+ Details

Name:	ck0000716133_AdditionalFuturePaymentsOnOperatingLeasesNotYetCommenced
Namespace Prefix:	ck0000716133_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Lease expiration year.

+ References

No definition available.

+ Details

Name:	ck0000716133_LeaseExpirationYear
Namespace Prefix:	ck0000716133_
Data Type:	xbrli:gYearItemType
Balance Type:	na
Period Type:	duration

- Definition

Term of lessee's operating and finance lease.

+ References

No definition available.

+ Details

Name:	ck0000716133_LesseeOperatingAndFinanceLeaseTermOfContract
Namespace Prefix:	ck0000716133_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Term of lessee's operating and finance lease renewal.

+ References

No definition available.

+ Details

Name:	ck0000716133_LesseeOperatingAndFinanceLeasesRenewalTerm
Namespace Prefix:	ck0000716133_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	duration

- Definition

Lessor Lease expiration period.

+ References

No definition available.

+ Details

Name:	ck0000716133_LessorLeaseExpirationPeriod
Namespace Prefix:	ck0000716133_
Data Type:	dtr-types:gYearListItemType
Balance Type:	na
Period Type:	duration

- Definition

Operating lease liability lessor revenue.

+ References

No definition available.

+ Details

Name:	ck0000716133_OperatingLeaseLiabilityLessorRevenue
Namespace Prefix:	ck0000716133_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Amount of lease income from operating, direct financing, and sales-type leases. Includes, but is not limited to, variable lease payments, interest income, profit (loss) recognized at commencement, and lease payments paid and payable to lessor.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 5
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479773/842-30-50-5

+ Details

Name:	us-gaap_LeaseIncome
Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	duration

- Definition

Term of lessee's finance lease not yet commenced, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (b)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-3

+ Details

Name:	us-gaap_LesseeFinanceLeaseLeaseNotYetCommencedTermOfContract1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 7A
-Subparagraph (c)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-7A

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-3

+ Details

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

- Definition

Indicates (true false) whether lessee has option to extend operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147478964/842-20-50-3

+ Details

Name:	us-gaap_LesseeOperatingLeaseExistenceOfOptionToExtend
Namespace Prefix:	us-gaap_
Data Type:	xbrli:booleanItemType
Balance Type:	na
Period Type:	duration

- Definition

Term of lessee's operating lease not yet commenced, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

+ Details

Name:	us-gaap_LesseeOperatingLeaseLeaseNotYetCommencedTermOfContract1
Namespace Prefix:	us-gaap_
Data Type:	xbrli:durationItemType
Balance Type:	na
Period Type:	instant

- Definition

Term of lessor's operating lease, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents reported fact of one year, five months, and thirteen days.

+ References

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
-Topic 842
-SubTopic 30
-Name Accounting Standards Codification
-Section 50
-Paragraph 3
-Subparagraph (a)(3)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479773/842-30-50-3

+ Details

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

- Definition

Amount of lessee's right to use underlying asset under operating lease.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Topic 842
-SubTopic 20
-Name Accounting Standards Codification
-Section 45
-Paragraph 1
-Subparagraph (a)
-Publisher FASB
-URI https://asc.fasb.org/1943274/2147479041/842-20-45-1

+ Details

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

- 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:	srt_ProductOrServiceAxis=us-gaap_RealEstateMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_EquipmentMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=ck0000716133_CellTowersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=ck0000716133_DesignatedSpaceOnThirdPartyCellTowersMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_PropertyPlantAndEquipmentByTypeAxis=us-gaap_VehiclesMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

Leases - Narratives (Details) - USD ($) $ in Millions	12 Months Ended
Leases - Narratives (Details) - USD ($) $ in Millions	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Lessee, Lease, Description [Line Items]
Lease expiration period	2094
Lessee, operating lease, existence of option to extend	true
Lessee, finance lease, renewal term	15 years
Additional future payments on operating leases not yet commenced	$ 1.1
Operating lease right-of-use assets	$ 77.4	$ 63.9
Lessor lease expiration period	2048
Lease income	$ 4.3	$ 3.4	$ 3.0
Additional future payments on finance leases not yet commenced	$ 0.3
Finance lease term	5 years
Lessor revenue	$ 0.8
Minimum [Member]
Lessee, Lease, Description [Line Items]
Operating lease term	3 years
Operating lease term	1 year
Maximum [Member]
Lessee, Lease, Description [Line Items]
Operating lease term	55 years
Operating lease term	30 years
Real Estate \| Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee operating and finance lease term of contract	1 year
Real Estate \| Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee operating and finance lease term of contract	70 years
Equipment [Member] \| Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee operating and finance lease term of contract	3 years
Equipment [Member] \| Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee operating and finance lease term of contract	10 years
Cell Towers [Member] \| Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee operating and finance lease term of contract	5 years
Cell Towers [Member] \| Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee operating and finance lease term of contract	21 years
Designated Space on Third Party Cell Towers [Member] \| Minimum [Member]
Lessee, Lease, Description [Line Items]
Lessee operating and finance lease term of contract	4 years
Designated Space on Third Party Cell Towers [Member] \| Maximum [Member]
Lessee, Lease, Description [Line Items]
Lessee operating and finance lease term of contract	55 years
Vehicles [Member]
Lessee, Lease, Description [Line Items]
Lessee operating and finance lease term of contract	5 years