CONSOLIDATED STATEMENTS OF STOCKHOLDER'S EQUITY (parenthetical) - USD ($) $ in Millions	Jan. 01, 2020	Dec. 31, 2019
RETAINED EARNINGS (ACCUMULATED DEFICIT)
Cumulative effect of new accounting principle in period of adoption, tax	$ 1	$ 1

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

No definition available.

Name:	lumn_CumulativeEffectOfNewAccountingPrincipleInPeriodOfAdoptionTax
Namespace Prefix:	lumn_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant