Property, Plant, and Equipment - Schedule (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 42,953	$ 57,934
Accumulated depreciation	(22,027)	(31,596)
Net property, plant and equipment	20,926	26,338
Land
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	751	848
Fiber, conduit and other outside plant
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	18,500	26,522
Central office and other network electronics
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	15,265	20,692
Support assets
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	7,147	8,261
Construction in progress
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 1,290	$ 1,611