Basis of Presentation (Details) - Jun. 30, 2015 $ in Millions	USD ($) state	USD ($) state
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Unamortized debt issuance expense	$ 110	$ 110
Geographic Areas, Revenues from External Customers [Abstract]
Number of states in which entity operates (states) \| state	14	14
CenturyLink, Inc. \| Maximum \| Change in allocation methodology for net periodic benefit service cost
Change in allocation methodology
Pension and other postretirement benefit service costs	$ 1	$ 2

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.

No definition available.

+ Details

Name:	ctq_ChangeinAllocationMethodologyLineItems
Namespace Prefix:	ctq_
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

- Definition

The amount of pension and other (such as medical, dental and life insurance) postretirement benefit service costs recognized during the period for defined benefit plans and other post-retirement benefit plans.

+ References

No definition available.

+ Details

Name:	ctq_PensionandOtherPostretirementBenefitServiceCosts
Namespace Prefix:	ctq_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration

- References

No definition available.

+ Details

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

- Definition

The number of states the entity operates in as of the balance sheet date.

+ References

No definition available.

+ Details

Name:	us-gaap_NumberOfStatesInWhichEntityOperates
Namespace Prefix:	us-gaap_
Data Type:	xbrli:integerItemType
Balance Type:	na
Period Type:	instant

- References

No definition available.

+ Details

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

- Definition

The remaining balance of debt issuance expenses that were capitalized and are being amortized against income over the lives of the respective bond issues. This does not include the amounts capitalized as part of the cost of the utility plant or asset.

+ 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 210.5-02.17)

-URI http://asc.fasb.org/extlink&oid=6877327&loc=d3e13212-122682

+ Details

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

- Details

Name:	us-gaap_RelatedPartyTransactionsByRelatedPartyAxis=ctq_CenturyLinkInc.Member
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	us-gaap_RangeAxis=us-gaap_MaximumMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type:

- Details

Name:	ctq_ChangeinAllocationMethodologybyTypeAxis=ctq_ChangeinAllocationMethodologyforNetPeriodicBenefitServiceCostMember
Namespace Prefix:
Data Type:	na
Balance Type:
Period Type: