Long-Term Debt and Credit Facilities - Schedule of Debt Repayments (Details) - USD ($) $ in Millions	9 Months Ended
Sep. 30, 2022	Sep. 30, 2021
Long-term Debt and Credit Facilities
Borrowings	$ 2,400
Repayments of debt	2,300
Gain from repayments of debt	9	$ 8
Repayments of debt	$ 3,705
Senior Notes \| 5.800% Senior Notes due 2022 (at Maturity)
Long-term Debt and Credit Facilities
Stated interest rate	5.80%
Repayments of debt	$ 1,400
Other
Long-term Debt and Credit Facilities
Repayments of debt	$ 30
Level 3 Financing, Inc. \| Senior Notes \| 5.375% Senior Notes due 2025
Long-term Debt and Credit Facilities
Stated interest rate	5.375%
Repayments of debt	$ 800
Level 3 Financing, Inc. \| Senior Notes \| 5.250% Senior Notes due 2026
Long-term Debt and Credit Facilities
Stated interest rate	5.25%
Repayments of debt	$ 775
Level 3 Financing, Inc. \| Term Loan \| Tranche B 2027 Term Loan
Long-term Debt and Credit Facilities
Repayments of debt	$ 700

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

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