Balance Sheet Components - Schedule of Net Book Value of Intangible Assets by Geographic Regions (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2024	Dec. 31, 2023	Dec. 31, 2022
Finite-lived Intangible Assets [Roll Forward]
Intangible assets, net beginning balance	$ 1,705	$ 1,898	$ 1,936
Impairment charges	$ (29)
Impairment, Intangible Asset, Finite-Lived, Statement of Income or Comprehensive Income Flag	Impairment charges
Amortization of intangibles	$ (208)	(208)	(205)
Impact of foreign currency exchange	(51)	7	(51)
Intangible assets, net ending balance	1,417	1,705	1,898
Entel Chile
Finite-lived Intangible Assets [Roll Forward]
Intangible assets acquired during period			153
Entel Peru
Finite-lived Intangible Assets [Roll Forward]
Intangible assets acquired during period			10
MainOne
Finite-lived Intangible Assets [Roll Forward]
Intangible assets acquired during period			55
Other asset acquisitions
Finite-lived Intangible Assets [Roll Forward]
Intangible assets acquired during period		8
Americas
Finite-lived Intangible Assets [Roll Forward]
Intangible assets, net beginning balance	1,216	1,349	1,328
Impairment charges	(29)
Amortization of intangibles	(140)	(140)	(138)
Impact of foreign currency exchange	(25)	0	(4)
Intangible assets, net ending balance	1,022	1,216	1,349
Americas | Entel Chile
Finite-lived Intangible Assets [Roll Forward]
Intangible assets acquired during period			153
Americas | Entel Peru
Finite-lived Intangible Assets [Roll Forward]
Intangible assets acquired during period			10
Americas | MainOne
Finite-lived Intangible Assets [Roll Forward]
Intangible assets acquired during period			0
Americas | Other asset acquisitions
Finite-lived Intangible Assets [Roll Forward]
Intangible assets acquired during period		7
EMEA
Finite-lived Intangible Assets [Roll Forward]
Intangible assets, net beginning balance	358	402	432
Impairment charges	0
Amortization of intangibles	(54)	(54)	(52)
Impact of foreign currency exchange	(16)	10	(33)
Intangible assets, net ending balance	288	358	402
EMEA | Entel Chile
Finite-lived Intangible Assets [Roll Forward]
Intangible assets acquired during period			0
EMEA | Entel Peru
Finite-lived Intangible Assets [Roll Forward]
Intangible assets acquired during period			0
EMEA | MainOne
Finite-lived Intangible Assets [Roll Forward]
Intangible assets acquired during period			55
EMEA | Other asset acquisitions
Finite-lived Intangible Assets [Roll Forward]
Intangible assets acquired during period		0
Asia-Pacific
Finite-lived Intangible Assets [Roll Forward]
Intangible assets, net beginning balance	131	147	176
Impairment charges	0
Amortization of intangibles	(14)	(14)	(15)
Impact of foreign currency exchange	(10)	(3)	(14)
Intangible assets, net ending balance	$ 107	131	147
Asia-Pacific | Entel Chile
Finite-lived Intangible Assets [Roll Forward]
Intangible assets acquired during period			0
Asia-Pacific | Entel Peru
Finite-lived Intangible Assets [Roll Forward]
Intangible assets acquired during period			0
Asia-Pacific | MainOne
Finite-lived Intangible Assets [Roll Forward]
Intangible assets acquired during period			$ 0
Asia-Pacific | Other asset acquisitions
Finite-lived Intangible Assets [Roll Forward]
Intangible assets acquired during period		$ 1