Sale of Data Centers and Colocation Business (Details) - USD ($) $ in Millions		3 Months Ended				6 Months Ended		8 Months Ended
	May 01, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Jun. 30, 2016	Jun. 30, 2017	Jun. 30, 2016	Jun. 30, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax expense		$ 23			$ 121	$ 167	$ 265
Less assets recorded as part of the failed-sale-leaseback		(40,744)		$ (39,194)		(40,744)		$ (40,744)
Total net amount of assets derecognized		7		2,376		7		7
Capital lease obligations		0		305		0		0
Total net imputed liabilities recognized		0		(419)		0		0
Sale and leaseback transaction loss, net						(119)	$ 0
Current amount due from affiliate		83				83		83
Sale-leaseback transaction rent expense		14
Colocation Business and Data Centers
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Net proceeds from sales of data centers and colocation business	$ 1,800
Income tax expense		32	$ 15	$ 18				65
Depreciation and amortization		17				67
Colocation Business and Data Centers | Disposal group disposed of by sale, not discontinued operations
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Goodwill	1,141
Property, plant and equipment	1,046
Other intangible assets	249
Other assets	62
Total net amount of assets derecognized	1,997
Capital lease obligations	294
Other liabilities	273
Total net imputed liabilities recognized	(81)
Disposal group, gain (loss) on disposal						(2)
SIS Holdings, LP | CenturyLink, Inc.
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
CenturyLink, Inc.'s value of minority stake		150				150		$ 150
Cyxtera Technologies
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Income tax expense		$ (63)				(63)
Less assets recorded as part of the failed-sale-leaseback	(501)
Less imputed financing obligations from the failed-sale-leaseback	$ (648)
Gain (Loss) on asset leaseback, failed-sale-leaseback transaction						(117)
Sale and leaseback transaction loss, net						$ (119)