Commitments and Contingencies (Details)				9 Months Ended	24 Months Ended
	Apr. 30, 2016	Jul. 17, 2013 USD ($)	Oct. 14, 2011 plaintiff	Sep. 30, 2016 USD ($) plaintiff lawsuit	Dec. 31, 2007 USD ($)
Loss Contingencies
Patents allegedly infringed (at least)				1
Unfavorable regulatory action
Loss Contingencies
Estimate of possible loss (per proceeding)				$ 100,000
William Douglas Fulghum, et al. v. Embarq Corporation
Loss Contingencies
Effect of modifications made to Embarq's benefits program (greater than)					$ 300,000,000
Abbott et al. v. Sprint Nextel et al.
Loss Contingencies
Number of plaintiffs | plaintiff			1,500
Comcast | Qwest Communications International Inc.
Loss Contingencies
Damages sought by plaintiff		$ 80,000,000
Interexchange Carriers | Subsidiaries of CenturyLInk, Inc.
Loss Contingencies
Number of plaintiffs | plaintiff				3
Number of lawsuits (approximately) | lawsuit				100
Missouri municipalities
Loss Contingencies
Opinion of counsel on ruling on one pending case	In an April 2016 ruling in connection with one of these pending cases, the court made findings which, if not overturned, will result in a tax liability to us well in excess of the contingent liability we have established. Following further proceedings at the district court, we plan to file an appeal and continue to vigorously defend against these claims. For a variety of reasons, we expect the outcome of our appeal to significantly reduce our ultimate exposure, although we can provide no assurances to this effect.