Property, Plant and Equipment (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
Property, Plant and Equipment, Net [Abstract]
Property, Plant and Equipment, Gross	$ 19,489us-gaap_PropertyPlantAndEquipmentGross	$ 17,329us-gaap_PropertyPlantAndEquipmentGross
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(9,629)	(9,089)
Net	9,860us-gaap_PropertyPlantAndEquipmentNet	8,240us-gaap_PropertyPlantAndEquipmentNet
Depreciation expense	713us-gaap_Depreciation	727us-gaap_Depreciation	659us-gaap_Depreciation
Land
Property, Plant and Equipment, Net [Abstract]
Property, Plant and Equipment, Gross	192	193
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	0	0
Net	192	193
Land Improvements
Property, Plant and Equipment, Net [Abstract]
Property, Plant and Equipment, Gross	73	72
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(50)	(47)
Net	23	25
Facility and Leasehold Improvements
Property, Plant and Equipment, Net [Abstract]
Property, Plant and Equipment, Gross	2,489	2,207
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(1,265)	(1,193)
Net	1,224	1,014
Network infrastructure
Property, Plant and Equipment, Net [Abstract]
Property, Plant and Equipment, Gross	8,941	8,505
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(3,447)	(3,279)
Net	5,494	5,226
Operating Equipment
Property, Plant and Equipment, Net [Abstract]
Property, Plant and Equipment, Gross	7,217	6,057
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(4,669)	(4,381)
Net	2,548	1,676
Furniture, Fixtures and Office Equipment
Property, Plant and Equipment, Net [Abstract]
Property, Plant and Equipment, Gross	255	196
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(177)	(168)
Net	78	28
Other
Property, Plant and Equipment, Net [Abstract]
Property, Plant and Equipment, Gross	29	22
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	(21)	(21)
Net	8	1
Construction-in-Progress
Property, Plant and Equipment, Net [Abstract]
Property, Plant and Equipment, Gross	293	77
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment	0	0
Net	$ 293	$ 77

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

-Name Accounting Standards Codification

-Topic 360

-SubTopic 10

-Section 50

-Paragraph 1

-Subparagraph (c)

-URI http://asc.fasb.org/extlink&oid=6391035&loc=d3e2868-110229

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The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Amount before accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

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Amount after accumulated depreciation, depletion and amortization of physical assets used in the normal conduct of business to produce goods and services and not intended for resale. Examples include, but are not limited to, land, buildings, machinery and equipment, office equipment, and furniture and fixtures.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher FASB

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