Long-Term Debt and Credit Facilities - Schedule of Long Term Debt (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2023	Dec. 31, 2022
Long-term Debt and Credit Facilities
Finance lease and other obligations	$ 306	$ 317
Unamortized discounts, net	(3)	(7)
Unamortized debt issuance costs	(162)	(169)
Total long-term debt	19,896	20,572
Less current maturities	(153)	(154)
Long-term debt, excluding current maturities	19,743	20,418
Line of credit \| Revolving Credit Facility
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 0	0
Line of credit \| Revolving Credit Facility \| LIBOR
Long-term Debt and Credit Facilities
Basis spread (as a percent)	2.00%
Term loan \| Term Loan A
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 977	$ 991
Long-term debt, weighted average interest rate	6.922%	6.384%
Term loan \| Term Loan A \| LIBOR
Long-term Debt and Credit Facilities
Basis spread (as a percent)	2.00%
Term loan \| Term Loan A-1
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 279	$ 283
Long-term debt, weighted average interest rate	6.922%	6.384%
Term loan \| Term Loan A-1 \| LIBOR
Long-term Debt and Credit Facilities
Basis spread (as a percent)	2.00%
Term loan \| Term Loan B
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 3,928	$ 3,941
Long-term debt, weighted average interest rate	7.172%	6.634%
Term loan \| Term Loan B \| LIBOR
Long-term Debt and Credit Facilities
Basis spread (as a percent)	2.25%
Senior notes \| 4.000% Senior Secured Notes Due 2027
Long-term Debt and Credit Facilities
Stated interest rate	4.00%
Long-term debt, gross	$ 1,250	$ 1,250
Senior notes \| Senior Notes Maturing 2023-2042
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 2,162	3,722
Senior notes \| Senior Notes Maturing 2023-2042 \| Minimum
Long-term Debt and Credit Facilities
Stated interest rate	4.50%
Senior notes \| Senior Notes Maturing 2023-2042 \| Maximum
Long-term Debt and Credit Facilities
Stated interest rate	7.65%
Level 3 Financing, Inc. \| Term loan \| Tranche B 2027 Term Loan
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 2,411	$ 2,411
Long-term debt, weighted average interest rate	6.672%	6.134%
Level 3 Financing, Inc. \| Term loan \| Tranche B 2027 Term Loan \| LIBOR
Long-term Debt and Credit Facilities
Basis spread (as a percent)	1.75%
Level 3 Financing, Inc. \| Senior notes \| Senior Notes, Maturing 2027-2030
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 2,415	$ 1,500
Level 3 Financing, Inc. \| Senior notes \| Senior Notes, Maturing 2027-2030 \| Minimum
Long-term Debt and Credit Facilities
Stated interest rate	3.40%
Level 3 Financing, Inc. \| Senior notes \| Senior Notes, Maturing 2027-2030 \| Maximum
Long-term Debt and Credit Facilities
Stated interest rate	10.50%
Level 3 Financing, Inc. \| Senior notes \| Senior Notes, Maturing 2027-2029
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 3,940	3,940
Level 3 Financing, Inc. \| Senior notes \| Senior Notes, Maturing 2027-2029 \| Minimum
Long-term Debt and Credit Facilities
Stated interest rate	3.625%
Level 3 Financing, Inc. \| Senior notes \| Senior Notes, Maturing 2027-2029 \| Maximum
Long-term Debt and Credit Facilities
Stated interest rate	4.625%
Qwest Corporation \| Term loan
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 215	$ 215
Long-term debt, weighted average interest rate	7.422%	6.64%
Qwest Corporation \| Term loan \| LIBOR
Long-term Debt and Credit Facilities
Basis spread (as a percent)	2.50%
Qwest Corporation \| Senior notes
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 1,986	$ 1,986
Qwest Corporation \| Senior notes \| Minimum
Long-term Debt and Credit Facilities
Stated interest rate	6.50%
Qwest Corporation \| Senior notes \| Maximum
Long-term Debt and Credit Facilities
Stated interest rate	7.75%
Qwest Capital Funding, Inc. \| Senior notes
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 192	$ 192
Qwest Capital Funding, Inc. \| Senior notes \| Minimum
Long-term Debt and Credit Facilities
Stated interest rate	6.875%
Qwest Capital Funding, Inc. \| Senior notes \| Maximum
Long-term Debt and Credit Facilities
Stated interest rate	7.75%

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Amount of short-term and long-term debt and lease obligation.

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Contractual interest rate for funds borrowed, under the debt agreement.

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Amount, after accumulated amortization, of debt discount (premium).

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Amount of long-term debt and lease obligation, classified as noncurrent.

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