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Commitments, Contingencies and Other Items (Details) plaintiff in Thousands, $ in Millions	1 Months Ended	3 Months Ended	9 Months Ended	12 Months Ended
	Feb. 28, 2017 USD ($) lawsuit	Jun. 30, 2019 USD ($)	Dec. 31, 2018 USD ($) lawsuit	Dec. 31, 2019 USD ($) patent plaintiff lawsuit property	Dec. 31, 2005 USD ($)
Commitments and Contingencies
Litigation liability			$ 123.0	$ 180.0
Litigation settlement charge				$ 71.0
Number of patents allegedly infringed, minimum \| patent				1
Number of properties with potential environmental liability \| property				200
Purchase obligations maturities
Total purchase commitments				$ 766.0
2020				247.0
2021 and 2022				261.0
2023 and 2024				85.0
2025 and thereafter				173.0
Right-of-Way Agreements
Future rental commitments
2020				174.0
2021				75.0
2022				72.0
2023				63.0
2024				52.0
2025 and thereafter				464.0
Total future minimum payments				900.0
Unfavorable regulatory action
Commitments and Contingencies
Reasonable expectation of loss, maximum per proceeding				$ 100.0
Louisiana State Court
Commitments and Contingencies
Loss contingency, new claims filed, number \| lawsuit			2
U.S. District Court for the District of Minnesota
Commitments and Contingencies
Litigation settlement, amount awarded to other party		$ 15.5
Litigation settlement, expense		$ 3.5
Number of members (more than) \| plaintiff				22
Missouri Municipalities \| Judicial ruling
Commitments and Contingencies
Pending cases, final order \| lawsuit	1
Litigation settlement, amount awarded to other party	$ 4.0
Peruvian Tax Litigation \| Pending litigation
Commitments and Contingencies
Loss contingency, damages sought, value					$ 26.0
Reasonable expectation of loss, maximum per proceeding				$ 7.0
CenturyLink, Inc. \| Interexchange Carriers
Commitments and Contingencies
Loss contingency, pending claims, number \| lawsuit				100
Level 3 Parent, LLC
Commitments and Contingencies
Loss contingency, damages sought, value				$ 50.0
Level 3 Parent, LLC \| Pending litigation \| Maximum \| Brazilian Tax Claims
Commitments and Contingencies
Loss contingency, range of possible loss, portion not accrued				$ 37.0