Property, Plant and Equipment - Schedule of Property, Plant, and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019
Property, plant and equipment
Gross property, plant and equipment	$ 57,934	$ 55,425
Accumulated depreciation	(31,596)	(29,346)
Net property, plant and equipment	26,338	26,079
Land
Property, plant and equipment
Gross property, plant and equipment	848	867
Fiber, conduit and other outside plant
Property, plant and equipment
Gross property, plant and equipment	$ 26,522	24,666
Fiber, conduit and other outside plant | Minimum
Property, plant and equipment
Depreciable Lives	15 years
Fiber, conduit and other outside plant | Maximum
Property, plant and equipment
Depreciable Lives	45 years
Central office and other network electronics
Property, plant and equipment
Gross property, plant and equipment	$ 20,692	19,608
Central office and other network electronics | Minimum
Property, plant and equipment
Depreciable Lives	3 years
Central office and other network electronics | Maximum
Property, plant and equipment
Depreciable Lives	10 years
Support assets
Property, plant and equipment
Gross property, plant and equipment	$ 8,261	7,984
Support assets | Minimum
Property, plant and equipment
Depreciable Lives	3 years
Support assets | Maximum
Property, plant and equipment
Depreciable Lives	30 years
Construction in progress
Property, plant and equipment
Gross property, plant and equipment	$ 1,611	$ 2,300