Basis of Presentation and Summary of Significant Accounting Policies (Details) $ in Millions		12 Months Ended
	Jan. 01, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)
Deferred Revenue Arrangement [Line Items]
Number of states in which entity operates		14
Advertising Costs
Advertising expense		$ 139	$ 91	$ 84
Accounts Receivable and Allowance for Doubtful Accounts
Threshold for determining accounts receivable as past due, days outstanding		30 days
Activation and installation charges | Minimum
Revenue Recognition
Customer relationship period for revenue recognition		3 years
Activation and installation charges | Maximum
Revenue Recognition
Customer relationship period for revenue recognition		7 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
Description of related party transaction				In 2015, we agreed to a plan to settle the outstanding pension and post-retirement affiliate obligations, net balance with QCII over a 30 year term. Under the plan, payments are scheduled to be made on a monthly basis.
Repayments on affiliate obligation		$ 87	$ 97
Forecast | Minimum | Accounting Standards Update 2014-09
Deferred Revenue Arrangement [Line Items]
Cumulative effect on retained earnings, before tax	$ 150
Forecast | Maximum | Accounting Standards Update 2014-09
Deferred Revenue Arrangement [Line Items]
Cumulative effect on retained earnings, before tax	$ 300