Face (par) amount of debt instrument at time of issuance.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Carrying value as of the balance sheet date of [accrued] interest payable on all forms of debt, including trade payables, that has been incurred and is unpaid. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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The amount for notes payable (written promise to pay), due to related parties. Used to reflect the current portion of the liabilities (due within one year or within the normal operating cycle if longer).

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The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

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

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Long-Term Debt and Revolving Promissory Note - Additional Information (Details) - USD ($)	3 Months Ended
	Sep. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Apr. 18, 2012
Long-term debt
Note payable - affiliate	$ 1,008,000,000	$ 965,000,000
Interest	58,000,000	77,000,000
Repayments of debt	1,300,000,000
Loans payable \| Qwest Corporation \| Affiliated entity
Long-term debt
Debt instrument, face amount			$ 965,000,000	$ 1,000,000,000
Note payable - affiliate	$ 1,008,000,000	$ 965,000,000
Weighted average interest rate	5.86%
Interest	$ 15,000,000
Senior notes \| Qwest Notes Due 2051
Long-term debt
Repayments of debt	$ 164,000,000
Stated interest rate	7.50%
Senior notes \| Qwest Notes due 2052
Long-term debt
Repayments of debt	$ 925,000,000
Stated interest rate	7.00%
Senior notes \| Qwest Notes 2035
Long-term debt
Repayments of debt	$ 250,000,000
Stated interest rate	7.25%