Employee Benefits (Details 3) (CenturyLink, Inc., 401(k) Plan, USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2014	Dec. 31, 2013	Dec. 31, 2012
CenturyLink, Inc. | 401(k) Plan
Defined Contribution Plan Disclosure [Line Items]
Expenses related to the 401(k) Plan	$ 47	$ 49	$ 46