Long-Term Debt and Credit Facilities - Schedule of Long Term Debt (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2023	Dec. 31, 2022
Long-term Debt and Credit Facilities
Finance lease and other obligations	$ 299	$ 317
Unamortized discounts, net	(3)	(7)
Unamortized debt issuance costs	(158)	(169)
Total long-term debt	20,053	20,572
Less current maturities	(154)	(154)
Long-term debt, excluding current maturities	19,899	20,418
Term Loan | Qwest Corporation
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 215	$ 215
Long-term debt, weighted average interest rate (as a percent)	7.717%	6.64%
Term Loan | SOFR | Qwest Corporation
Long-term Debt and Credit Facilities
Basis spread (as a percent)	2.50%
Senior Notes | Qwest Corporation
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 1,986	$ 1,986
Senior Notes | Qwest Corporation | Minimum
Long-term Debt and Credit Facilities
Stated interest rate (as a percent )	6.50%
Senior Notes | Qwest Corporation | Maximum
Long-term Debt and Credit Facilities
Stated interest rate (as a percent )	7.75%
Senior Notes | Qwest Capital Funding, Inc.
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 192	192
Senior Notes | Qwest Capital Funding, Inc. | Minimum
Long-term Debt and Credit Facilities
Stated interest rate (as a percent )	6.875%
Senior Notes | Qwest Capital Funding, Inc. | Maximum
Long-term Debt and Credit Facilities
Stated interest rate (as a percent )	7.75%
Revolving Credit Facility | Line of Credit
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 200	0
Long-term debt, weighted average interest rate (as a percent)	7.262%
Revolving Credit Facility | Line of Credit | SOFR
Long-term Debt and Credit Facilities
Basis spread (as a percent)	2.00%
Term Loan A | Term Loan
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 962	$ 991
Long-term debt, weighted average interest rate (as a percent)	7.217%	6.384%
Term Loan A | Term Loan | SOFR
Long-term Debt and Credit Facilities
Basis spread (as a percent)	2.00%
Term Loan A-1 | Term Loan
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 275	$ 283
Long-term debt, weighted average interest rate (as a percent)	7.217%	6.384%
Term Loan A-1 | Term Loan | SOFR
Long-term Debt and Credit Facilities
Basis spread (as a percent)	2.00%
Term Loan B | Term Loan
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 3,916	$ 3,941
Long-term debt, weighted average interest rate (as a percent)	7.467%	6.634%
Term Loan B | Term Loan | SOFR
Long-term Debt and Credit Facilities
Basis spread (as a percent)	2.25%
4.000% Senior Secured Notes Due 2027 | Senior Notes
Long-term Debt and Credit Facilities
Stated interest rate (as a percent )	4.00%
Long-term debt, gross	$ 1,250	$ 1,250
Tranche B 2027 Term Loan | Term Loan | Level 3 Financing, Inc.
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 2,411	$ 2,411
Long-term debt, weighted average interest rate (as a percent)	6.967%	6.134%
Tranche B 2027 Term Loan | Term Loan | SOFR | Level 3 Financing, Inc.
Long-term Debt and Credit Facilities
Basis spread (as a percent)	1.75%
Senior Notes, Maturing 2027-2030 | Senior Notes | Level 3 Financing, Inc.
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 2,425	$ 1,500
Senior Notes, Maturing 2027-2030 | Senior Notes | Level 3 Financing, Inc. | Minimum
Long-term Debt and Credit Facilities
Stated interest rate (as a percent )	3.40%
Senior Notes, Maturing 2027-2030 | Senior Notes | Level 3 Financing, Inc. | Maximum
Long-term Debt and Credit Facilities
Stated interest rate (as a percent )	10.50%
Senior Notes Maturing 2025-2042 | Senior Notes
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 2,143	3,722
Senior Notes Maturing 2025-2042 | Senior Notes | Minimum
Long-term Debt and Credit Facilities
Stated interest rate (as a percent )	4.50%
Senior Notes Maturing 2025-2042 | Senior Notes | Maximum
Long-term Debt and Credit Facilities
Stated interest rate (as a percent )	7.65%
Senior Notes, Maturing 2027-2029 | Senior Notes | Level 3 Financing, Inc.
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 3,940	$ 3,940
Senior Notes, Maturing 2027-2029 | Senior Notes | Level 3 Financing, Inc. | Minimum
Long-term Debt and Credit Facilities
Stated interest rate (as a percent )	3.625%
Senior Notes, Maturing 2027-2029 | Senior Notes | Level 3 Financing, Inc. | Maximum
Long-term Debt and Credit Facilities
Stated interest rate (as a percent )	4.625%