Background and Summary of Significant Accounting Policies (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022	Dec. 17, 2024	Jan. 01, 2024	Feb. 25, 2019
Accounting Policies [Line Items]
Advertising expense	$ 94	$ 87	$ 62
Book overdrafts	$ 1	$ 0
Accounts receivable, period past due (in days)	30 days
Common stock, par value (in dollars per share)	$ 0.00	$ 1.00		$ 1.00
Unissued shares of century link common stock (in shares)	41,000,000
Preferred stock dividends (in dollars per share)	$ 25
Number of shares issued per share of common stock						1
Depreciation	$ 1,900	$ 1,900	$ 2,100
Diluted loss per common share (in dollars per share)	$ (0.06)	$ (10.48)	$ (1.54)
Service Life
Accounting Policies [Line Items]
Depreciation	$ (63)
Depreciation, net of tax	$ (48)
Diluted loss per common share (in dollars per share)	$ 0.05
Fiber Network Assets
Accounting Policies [Line Items]
Property, plant and equipment, useful life (in years)		25 years			30 years
Capitalized Software
Accounting Policies [Line Items]
Estimated useful life (in years)	7 years
Minimum
Accounting Policies [Line Items]
Contract term (in years)	1 year
Minimum | Customer Relationships
Accounting Policies [Line Items]
Estimated useful life (in years)	7 years
Minimum | Other Intangible Assets
Accounting Policies [Line Items]
Estimated useful life (in years)	9 years
Maximum
Accounting Policies [Line Items]
Contract term (in years)	5 years
Customer relationship period for revenue recognition (in years)	20 years
Maximum | Customer Relationships
Accounting Policies [Line Items]
Estimated useful life (in years)	14 years
Maximum | Other Intangible Assets
Accounting Policies [Line Items]
Estimated useful life (in years)	20 years
Weighted Average | Mass Markets
Accounting Policies [Line Items]
Length of customer life (in months)	50 months
Weighted Average | Business
Accounting Policies [Line Items]
Length of customer life (in months)	35 months