Property, Plant and Equipment (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Property, plant and equipment
Property, plant and equipment	$ 12,182	$ 11,157
Accumulated depreciation	(4,808)	(3,956)
Net property, plant and equipment	7,374	7,201
Depreciation expense	986	1,048	$ 1,099
Land
Property, plant and equipment
Property, plant and equipment	349	350
Fiber, conduit and other outside plant
Property, plant and equipment
Property, plant and equipment	$ 5,362	4,640
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
Property, plant and equipment	$ 3,614	3,362
Central office and other network electronics | Minimum
Property, plant and equipment
Depreciable lives	4 years
Central office and other network electronics | Maximum
Property, plant and equipment
Depreciable lives	10 years
Support assets
Property, plant and equipment
Property, plant and equipment	$ 2,584	2,496
Support assets | Minimum
Property, plant and equipment
Depreciable lives	5 years
Support assets | Maximum
Property, plant and equipment
Depreciable lives	30 years
Construction in progress
Property, plant and equipment
Property, plant and equipment	$ 273	$ 309