Threshold period for determining trade accounts receivable as past due in 'PnYnMnDTnHnMnS' format

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- Definition

Cumulative Effect of New Accounting Principle in Period of Adoption, Tax

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- Definition

Revenue from Contract with Customer, Contract Term

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- Definition

Revenue from Contract with Customer, Length of Customer Life

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- Definition

Represents the customer relationship period considered for recognition of revenue.

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- Definition

Amount charged to advertising expense for the period, which are expenses incurred with the objective of increasing revenue for a specified brand, product or product line.

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Amount after tax of increase (decrease) to equity or (increase) decrease to net assets, resulting from the cumulative effect adjustment of a new accounting principle applied in the period of adoption.

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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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- Definition

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

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- Definition

Amount of transactions with related party during the financial reporting period.

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A description of the related party transaction, including transactions to which no amounts or nominal amounts were ascribed and such other information deemed necessary to an understanding of the effects of the transactions on the financial statements. Examples of common related party transactions are, sales, purchases and transfers of realty and personal property, services received or furnished, loans and leases to and from top management and affiliates.

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Background and Summary of Significant Accounting Policies - Additional Information (Details) $ in Millions	12 Months Ended
	Dec. 31, 2018 USD ($) state	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015
Deferred Revenue Arrangement [Line Items]
Number of states in which entity operates \| state	14
Advertising Costs
Advertising expense	$ 58	$ 139	$ 91
Accounts Receivable and Allowance for Doubtful Accounts
Threshold for determining accounts receivable as past due, days outstanding	30 days
Minimum
Revenue Recognition
Contract term	1 year
Customer relationship period for revenue recognition	10 years
Maximum
Revenue Recognition
Contract term	7 years
Customer relationship period for revenue recognition	20 years
Qwest Communications International, Inc.
Affiliate Transactions
Description of related party transaction				In 2015, we agreed to a plan to settle the outstanding affiliate obligations, net balance with QCII over a 30 year term. Under the plan, payments are scheduled to be made on a monthly basis.
Pension, Supplemental and Other Postretirement Benefit Plans \| Qwest Communications International, Inc.
Affiliate Transactions
Repayments on affiliate obligation	$ 87	87
Consumer Customers \| Average
Revenue Recognition
Customer life	30 months
Business Customer
Revenue Recognition
Customer life	49 months
Business Customer \| Minimum
Revenue Recognition
Customer life	49 months
Retained Earnings
Affiliate Transactions
Cumulative effect of ASU 2014-09	$ 141	0	0
Cumulative net effect of adoption of ASU 2014-09, tax	49	$ 0	$ 0
Retained Earnings \| Accounting Standards Update 2014-09
Affiliate Transactions
Cumulative effect of ASU 2014-09	141
Cumulative net effect of adoption of ASU 2014-09, tax	$ 49