Commitments and Contingencies (Details) In Millions, unless otherwise specified	12 Months Ended				12 Months Ended		24 Months Ended	0 Months Ended		1 Months Ended			12 Months Ended
	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2014 CenturyLink, Inc. security shareholder_derivative_action	Dec. 31, 2013 Pending litigation related to Federal Communications Act CenturyLink, Inc. USD ($)	Dec. 31, 2009 Pending litigation related to Federal Communications Act CenturyLink, Inc. USD ($)	Dec. 31, 2007 William Douglas Fulghum, et al. v. Embarq Corporation USD ($)	Oct. 14, 2011 Abbott et al. v. Sprint Nextel et al. plaintiff	Jul. 16, 2013 Comcast MO Group, Inc. Qwest Communications International Inc USD ($)	Feb. 27, 2014 KPNQwest Qwest Communications International Inc USD ($)	Feb. 27, 2014 KPNQwest Qwest Communications International Inc EUR (€)	Dec. 31, 2014 KPNQwest Qwest Communications International Inc USD ($)	Dec. 31, 2014 Cargill Financial Markets, Plc and Citibank, N.A. USD ($)	Dec. 31, 2014 Cargill Financial Markets, Plc and Citibank, N.A. EUR (€)	Dec. 31, 2014 Fiber-optic cable installation state
Commitments and Contingencies
Number of lawsuits filed (lawsuits)						2
Charges claimed against Sprint Nextel						$ 34
Proceeds from legal settlements					24
Effect of modifications made to Embarq's benefits program, greater than							300
Number of plaintiffs have alleged breach of fiduciary duty (plaintiffs)								1,500
Number of Plaintiffs, Limited Discovery								80
Litigation Matters Assumed in Qwest Acquisition
Damages sought by plaintiff									80				266	219
Payments for legal settlements										235	171
Legal reserve, KPNQwest litigation settlement												235
Number of states in which service is provided (states)															34
Number of states in which final approval of settlements received (states)															31
Number of states where an action is pending (states)															2
Number of states in which actions are not currently pending															1
Number of securities actions in which the company is the defendant (securities)				1
Number of shareholder derivative actions in which the company is the defendant (shareholder derivative actions)				4
Capital lease activity
Assets acquired through capital leases	37	12	209
Depreciation expense	126	136	150
Cash payments towards capital leases	118	119	113
Assets included in property, plant and equipment	850	877
Accumulated depreciation	393	338
Future annual minimum payments under capital lease arrangements
2015	104
2016	76
2017	74
2018	72
2019	61
2020 and thereafter	284
Total minimum payments	671
Less: amount representing interest and executory costs	(182)
Present value of minimum payments	489
Less: current portion	(73)
Long-term portion	416
Operating Leases
Rent expense	446	455	445
Sublease rental income	14	16	18
Future rental commitments
2015	311
2016	280
2017	257
2018	233
2019	202
2020 and thereafter	974
Total future minimum payments	2,257
Minimum sublease rentals due in the future under non-cancelable subleases	91
Purchase obligations
Total purchase commitments	407
2015	141
2016 and 2017	154
2018 and 2019	50
2020 and thereafter	$ 62