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
Gross property, plant and equipment	$ 36,718		$ 34,307
Accumulated depreciation	(18,285)		(15,661)
Net property, plant and equipment	18,433		18,646
Depreciation expense	2,958		2,952		3,070
Land
Property, plant and equipment
Gross property, plant and equipment	575		585
Fiber, conduit and other outside plant
Property, plant and equipment
Gross property, plant and equipment	15,151	[1]	14,187	[1]
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
Gross property, plant and equipment	13,248	[2]	12,178	[2]
Central office and other network electronics | Minimum
Property, plant and equipment
Depreciable Lives	3 years
Central office and other network electronics | Maximum
Property, plant and equipment
Depreciable Lives	10 years
Support assets
Property, plant and equipment
Gross property, plant and equipment	6,578	[3]	6,420	[3]
Support assets | Minimum
Property, plant and equipment
Depreciable Lives	3 years
Support assets | Maximum
Property, plant and equipment
Depreciable Lives	30 years
Construction in progress
Property, plant and equipment
Gross property, plant and equipment	1,166	[4]	937	[4]
Qwest Corporation | Office building
Property, plant and equipment
Impairment of office building	17
CenturyLink, Inc. | Office building
Property, plant and equipment
Sale price specified in sales agreement	$ 12

[1] Fiber, conduit and other outside plant consists of fiber and metallic cable, conduit, poles and other supporting structures.

[2] Central office and other network electronics consists of circuit and packet switches, routers, transmission electronics and electronics providing service to customers.

[3] Support assets consist of buildings, data centers, computers and other administrative and support equipment.

[4] Construction in progress includes inventory held for construction and property of the aforementioned categories that has not been placed in service as it is still under construction.