Background and Summary of Significant Accounting Policies (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018	Feb. 25, 2019
Finite-Lived Intangible Assets [Line Items]
Advertising expense	$ 56	$ 56	$ 62
Book overdraft balance	$ 0	0
Accounts receivable, period past due	30 days
Unissued shares of CenturyLink common stock (in shares)	36,000,000
Preferred stock dividends (in dollars per share)	$ 25
Number of shares issued per share of common stock					1
Stockholders' equity	$ 11,840	11,162	13,470
Income tax expense	668	450	503
Retained Earnings (Accumulated Deficit)
Finite-Lived Intangible Assets [Line Items]
Stockholders' equity	$ (5,998)	$ (8,031)	(6,814)	$ (1,643)
Income tax expense			2	37
Retained Earnings (Accumulated Deficit) | Cumulative Effect, Period of Adoption, Adjustment
Finite-Lived Intangible Assets [Line Items]
Stockholders' equity			9	96
Income tax expense			$ 2	$ (37)
Capitalized software
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	7 years
Minimum
Finite-Lived Intangible Assets [Line Items]
Contract term	1 year
Customer relationship period for revenue recognition	10 years
Minimum | Customer relationships
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	7 years
Minimum | Other intangible assets
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	4 years
Maximum
Finite-Lived Intangible Assets [Line Items]
Contract term	5 years
Customer relationship period for revenue recognition	20 years
Maximum | Customer relationships
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	14 years
Maximum | Other intangible assets
Finite-Lived Intangible Assets [Line Items]
Estimated useful life	20 years
Weighted Average | Mass Markets
Finite-Lived Intangible Assets [Line Items]
Length of customer life	30 months
Weighted Average | Business
Finite-Lived Intangible Assets [Line Items]
Length of customer life	29 months