Commitments, Contingencies and Other Items - Lawsuits (Details) $ in Millions	3 Months Ended
	Mar. 31, 2019 USD ($) Employee contract
Loss Contingencies [Line Items]
Estimated litigation liability	$ 70
Peruvian Tax Litigation, Before Interest | Pending Litigation
Loss Contingencies [Line Items]
Asserted claim	26
Peruvian Tax Litigation | Pending Litigation
Loss Contingencies [Line Items]
Asserted claim	10
Brazilian Tax Claims
Loss Contingencies [Line Items]
Estimate of possible loss	$ 37
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