Long-Term Debt and Credit Facilities - Level 3 Financing Credit Agreement (Details) - Level 3 Financing, Inc. - Term Loan B-3 - Term Loan - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2025	Dec. 31, 2024
Long-term Debt and Credit Facilities
Long-term debt, gross	$ 2,400	$ 0
Basis spread (as a percent)	4.25%
Debt instrument, floor interest rate (as a percent)	0.50%
Debt instrument, prepayment premium (as a percent)	1.00%
Prepayment from net cash proceeds of certain asset sales (as a percent)	100.00%
Prepayment from net cash proceeds of certain debt issuances (as a percent)	100.00%
Federal Funds Rate
Long-term Debt and Credit Facilities
Basis spread (as a percent)	0.50%
One Month SOFR Rate
Long-term Debt and Credit Facilities
Basis spread (as a percent)	1.00%
SOFR
Long-term Debt and Credit Facilities
Basis spread (as a percent)	4.25%