Repurchase of CenturyLink Common Stock (Details) - Share repurchase program authorized February 2014 - USD ($) $ / shares in Units, shares in Millions, $ in Millions	12 Months Ended	18 Months Ended
	Dec. 31, 2015	Dec. 07, 2015	Feb. 28, 2014
Equity, Class of Treasury Stock [Line Items]
Stock repurchase program, period in force	24 months
Stock repurchases, aggregate authorized amount			$ 1,000
Stock repurchased and retired during period, shares	27.1	32.3
Stock repurchased and retired during period, value	$ 800
Stock repurchased and retired during period, average cost per share	$ 29.56	$ 30.99