Commitments, Contingencies and Other Items (Details)	9 Months Ended
	Sep. 30, 2020 USD ($) contract Employee subsidiary	Dec. 31, 2019 USD ($)	Dec. 31, 2005 subsidiary
Loss Contingencies [Line Items]
Estimated litigation liability	$ 55,000,000
Letters of credit outstanding, amount	17,000,000	$ 23,000,000
Collateralized financings	11,000,000	$ 18,000,000
Unfavorable Regulatory Action
Loss Contingencies [Line Items]
Estimate of possible loss	100,000
Peruvian Tax Litigation, Before Interest | Pending Litigation
Loss Contingencies [Line Items]
Number of subsidiaries with tax assessment | subsidiary			1
Asserted claim	26,000,000
Estimate of possible loss	3,000,000
Brazilian Tax Claims | Minimum
Loss Contingencies [Line Items]
Estimate of possible loss	16,000,000
Brazilian Tax Claims | Maximum
Loss Contingencies [Line Items]
Estimate of possible loss	$ 44,000,000
Brazilian Tax Claims | Pending Litigation
Loss Contingencies [Line Items]
Number of subsidiaries with tax assessment | subsidiary	1
United States of America ex rel., Stephen Bishop v. Level 3 Communications, Inc. et al.
Loss Contingencies [Line Items]
Number of former employees names in lawsuit | Employee	2
Number of government contracts in question | contract	2
Damages sought, value	$ 50,000,000
Number of former employees with plea agreements | Employee	1