Employee Benefits - Pension and Post-Retirement Benefits (Details) - USD ($)	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
CenturyLink, Inc.
Employee Benefits
Allocated expenses by parent entities (as a percent)	69.00%	70.00%	70.00%
Pension Plan
Employee Benefits
Defined benefit plan, service cost	$ 38,000,000	$ 41,000,000	$ 40,000,000
Pension Plan | CenturyLink, Inc.
Employee Benefits
Employer contributions to benefit plan	0	0
Pension Plan | CenturyLink, Inc.
Employee Benefits
Unfunded status	1,100,000,000	1,700,000,000
Post-Retirement Benefit Plan
Employee Benefits
Defined benefit plan, service cost	10,000,000	10,000,000	$ 11,000,000
Post-Retirement Benefit Plan | CenturyLink, Inc.
Employee Benefits
Unfunded status	$ 2,800,000,000	3,000,000,000
Pension, Supplemental and Other Postretirement Benefit Plans | Qwest Communications International, Inc.
Employee Benefits
Pension settlement term	30 years
Repayments on affiliate obligation	$ 46,000,000	$ 71,000,000