Property, Plant and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2025	Dec. 31, 2024	Dec. 31, 2023
Property, Plant and Equipment [Abstract]
Depreciation expense	$ 652	$ 712	$ 756
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	16,356	17,775
Accumulated depreciation	(8,910)	(8,910)
Net property, plant and equipment	7,446	8,865
Land
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	328	329
Fiber, conduit and other outside plant
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 7,400	8,246
Fiber, conduit and other outside plant | Minimum
Property, Plant and Equipment [Line Items]
Depreciable Lives	15 years
Fiber, conduit and other outside plant | Maximum
Property, Plant and Equipment [Line Items]
Depreciable Lives	45 years
Central office and other network electronics
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 5,487	5,792
Central office and other network electronics | Minimum
Property, Plant and Equipment [Line Items]
Depreciable Lives	7 years
Central office and other network electronics | Maximum
Property, Plant and Equipment [Line Items]
Depreciable Lives	10 years
Support assets
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 2,902	2,878
Support assets | Minimum
Property, Plant and Equipment [Line Items]
Depreciable Lives	3 years
Support assets | Maximum
Property, Plant and Equipment [Line Items]
Depreciable Lives	30 years
Construction in progress
Property, Plant and Equipment [Line Items]
Gross property, plant and equipment	$ 239	$ 530