Basis of Presentation and Summary of Significant Accounting Policies (Details 5) shares in Millions	Dec. 31, 2015 $ / shares shares
Common Stock
Class of Stock [Line Items]
Unissued shares of CenturyLink common stock	4
Common Stock | Stock compensation plan
Class of Stock [Line Items]
Unissued shares of CenturyLink common stock	25
Preferred Stock
Class of Stock [Line Items]
Preferential preferred stock distribution (in dollars per share) | $ / shares	$ 25