Property, Plant and Equipment - Net Property, Plant and Equipment (Details) - USD ($) $ in Millions	10 Months Ended	12 Months Ended
	Oct. 31, 2017	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Property, Plant and Equipment, Net [Abstract]
Property, plant and equipment		$ 9,555
Accumulated depreciation		(143)
Net property, plant and equipment		9,412
Depreciation expense		143
Land
Property, Plant and Equipment, Net [Abstract]
Property, plant and equipment		348
Fiber conduit and other outside plant
Property, Plant and Equipment, Net [Abstract]
Property, plant and equipment		$ 4,750
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		$ 2,134
Central office and other network electronics | Minimum
Property, Plant and Equipment [Line Items]
Depreciable Lives		3 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		$ 2,019
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		$ 304
Predecessor
Property, Plant and Equipment, Net [Abstract]
Property, plant and equipment			$ 21,388
Accumulated depreciation			(11,249)
Net property, plant and equipment			10,139
Depreciation expense	$ 850		948	$ 855
Predecessor | Land
Property, Plant and Equipment, Net [Abstract]
Property, plant and equipment			179
Predecessor | Fiber conduit and other outside plant
Property, Plant and Equipment, Net [Abstract]
Property, plant and equipment			9,110
Predecessor | Central office and other network electronics
Property, Plant and Equipment, Net [Abstract]
Property, plant and equipment			8,846
Predecessor | Support assets
Property, Plant and Equipment, Net [Abstract]
Property, plant and equipment			3,023
Predecessor | Construction-in-progress
Property, Plant and Equipment, Net [Abstract]
Property, plant and equipment			$ 230