Property, Plant and Equipment - Net Property, Plant and Equipment (Details) - USD ($) $ in Millions	2 Months Ended	10 Months Ended	12 Months Ended
	Dec. 31, 2017	Oct. 31, 2017	Dec. 31, 2019	Dec. 31, 2018
Property, Plant and Equipment, Net [Abstract]
Property, plant and equipment			$ 11,761	$ 10,474
Accumulated depreciation			(1,825)	(1,021)
Net property, plant and equipment			9,936	9,453
Depreciation expense	$ 143	$ 850	804	906
Land
Property, Plant and Equipment, Net [Abstract]
Property, plant and equipment			336	339
Fiber conduit and other outside plant
Property, Plant and Equipment, Net [Abstract]
Property, plant and equipment			$ 5,226	5,262
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, Net [Abstract]
Property, plant and equipment			$ 2,687	1,986
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, Net [Abstract]
Property, plant and equipment			$ 2,419	2,327
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, Net [Abstract]
Property, plant and equipment			$ 1,093	$ 560