Long-Term Debt and Credit Facilities - Lumen Credit Agreements (Details) - USD ($)	Mar. 22, 2024	Jun. 30, 2024	Dec. 31, 2023
Prepaid on or Prior to the 12-Month Anniversary of the Effective Date | Level 3 Financing, Inc.
Long-term Debt and Credit Facilities
Prepayment premium, rate	2.00%
Prepaid After the 12-Month Anniversary and on or Prior to the 24-Month Anniversary of the Effective Date | Level 3 Financing, Inc.
Long-term Debt and Credit Facilities
Prepayment premium, rate	1.00%
Superpriority Term Loan A | Term Loan
Long-term Debt and Credit Facilities
Debt instrument periodic payment (as a percent)	1.25%
Superpriority Term Loan B | Term Loan
Long-term Debt and Credit Facilities
Debt instrument periodic payment (as a percent)	0.25%
Series A Revolving Credit Facility
Long-term Debt and Credit Facilities
Maximum borrowing capacity		$ 489,000,000
Series A Revolving Credit Facility | Line of Credit
Long-term Debt and Credit Facilities
Long-term debt, gross		0	$ 0
Series B Revolving Credit Facility
Long-term Debt and Credit Facilities
Maximum borrowing capacity		467,000,000
Series B Revolving Credit Facility | Line of Credit
Long-term Debt and Credit Facilities
Long-term debt, gross		$ 0	$ 0