Long-Term Debt and Credit Facilities - Lumen Credit Agreements (Details)	Mar. 22, 2024 credit_facility	Jun. 30, 2025 USD ($)	Dec. 31, 2024 USD ($)
Series A Revolving Credit Facility
Long-term Debt and Credit Facilities
Maximum borrowing capacity		$ 489,000,000
Series B Revolving Credit Facility
Long-term Debt and Credit Facilities
Maximum borrowing capacity		465,000,000
Term Loan | Superpriority Secured Term Loan Facility
Long-term Debt and Credit Facilities
Number of credit facilities | credit_facility	2
Term Loan | Lumen TLA
Long-term Debt and Credit Facilities
Debt instrument periodic payment (as a percent)	1.25%
Term Loan | Lumen TLB
Long-term Debt and Credit Facilities
Debt instrument periodic payment (as a percent)	0.25%
Line of Credit | Series A Revolving Credit Facility
Long-term Debt and Credit Facilities
Long-term debt, gross		0	$ 0
Line of Credit | Series B Revolving Credit Facility
Long-term Debt and Credit Facilities
Long-term debt, gross		$ 0	$ 0