Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Face (par) amount of debt instrument at time of issuance.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef
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Contractual interest rate for funds borrowed, under the debt agreement.

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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.

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Face (par) amount of the original debt instrument that was repurchased.

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Maximum borrowing capacity under the credit facility without consideration of any current restrictions on the amount that could be borrowed or the amounts currently outstanding under the facility.

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Weighted average interest rate of long-term debt outstanding calculated at point in time.

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The cash inflow from additional borrowings, net of cash paid to third parties in connection with debt origination.

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Long-Term Debt and Credit Facilities - Additional Information (Details) - USD ($) $ in Millions	Jan. 29, 2018	Mar. 31, 2018	Jan. 21, 2018	Dec. 31, 2017
CenturyLink, Inc. \| Line of credit
Long-term Debt and Credit Facilities
Long-term debt, weighted average interest rate (percent)				4.186%
CenturyLink, Inc. \| Line of credit \| New Revolving Credit Facility
Long-term Debt and Credit Facilities
Long-term debt, gross		$ 0		$ 405
CenturyLink, Inc. \| Revolving credit facility \| New Revolving Credit Facility
Long-term Debt and Credit Facilities
Line of credit facility, maximum borrowing capacity	$ 2,168
CenturyLink, Inc. \| Medium-term notes
Long-term Debt and Credit Facilities
Proceeds from debt, net of issuance costs	132
CenturyLink, Inc. \| Medium-term notes \| Term Loan A
Long-term Debt and Credit Facilities
Long-term debt, gross		$ 1,686		1,575
Stated interest rate (percent)		4.627%
Debt instrument, face amount	$ 1,707
Embarq Corporation \| First mortgage bonds
Long-term Debt and Credit Facilities
Long-term debt, gross		$ 138		$ 151
Embarq Corporation \| First mortgage bonds \| 8.77% Notes due 2017
Long-term Debt and Credit Facilities
Debt instrument, repurchased face amount			$ 13
Stated interest rate (percent)			8.77%