Employee Benefits	12 Months Ended
Employee Benefits	Dec. 31, 2019
Retirement Benefits [Abstract]
Employee Benefits	Employee Benefits Defined Contribution Plans We offer eligible employees the opportunity to participate in a defined contribution retirement plan subject to the provisions of Section 401(k) of the Internal Revenue Code, as amended ("401(k) Plan"). Each employee is eligible to contribute, on a tax deferred basis, a portion of annual earnings generally not to exceed $19,000 in 2019, $18,500 in 2018 and $18,000 in 2017. We match 100% of a participant’s pre-tax and/or Roth contributions of the first 1% of the participant’s eligible compensation plus 60% of the same contributions that exceed 1% up to a maximum of 6% of the participant’s eligible compensation. Effective December 31, 2017, the Level 3 Communications, Inc. 401(k) Profit Sharing Plan and Trust assets merged with the CenturyLink, Inc. Dollars & Sense 401(k) Plan. Those employees eligible to contribute to the Level 3 Plan at December 31, 2017 were automatically enrolled in the CenturyLink Plan at January 1, 2018. Provisions of the Level 3 Plan document regarding eligibility, participant and employer contributions, vesting, and benefit payments did not materially change and protected provisions applicable to Level 3 and its predecessor Plans remained grandfathered as required by law. Prior to the CenturyLink acquisition on November 1, 2017, our matching contributions were made with Level 3 common stock based on the closing stock price on each pay date. After our acquisition, matching contributions were made in cash. We made 401(k) Plan matching contributions of $7 million for the successor period ended December 31, 2017 and $30 million for the predecessor period ended October 31, 2017. Matching contributions recorded as compensation expense in cost of services totaled $1 million for the successor period ended December 31, 2017 and $4 million for the predecessor period ended October 31, 2017. Matching contributions included in selling, general and administrative expenses totaled $5 million for the successor period ended December 31, 2017 and $26 million for the predecessor period ended October 31, 2017. Matching contributions for the year ended December 31, 2019 were $29 million, of which $11 million was recognized in cost of sales and $18 million in selling, general and administrative costs. Matching contributions for the year ended December 31, 2018 were $26 million, of which $10 million was recognized in cost of sales and $16 million in selling, general and administrative costs. Other defined contribution plans we sponsored are individually not significant. On an aggregate basis, the expense we recorded relating to these plans was approximately $6 million and $5 million for the years ended December 31, 2019 and 2018, respectively, $1 million for the successor period ended December 31, 2017 and $5 million for the predecessor period ended October 31, 2017. Defined Benefit Plans We have certain contributory and non-contributory employee pension plans, which are not significant to our financial position or operating results. We recognize in our balance sheet the funded status of our defined benefit post-retirement plans, which is measured as the difference between the fair value of the plan assets and the plan benefit obligations. We are also required to recognize changes in the funded status within accumulated other comprehensive income, net of tax, to the extent such changes are not recognized in earnings as components of periodic net benefit cost. The fair value of the plan assets was $122 million and $133 million as of December 31, 2019 and 2018, respectively. The total plan benefit obligations were $140 million and $144 million as of December 31, 2019 and 2018, respectively. Therefore, the net unfunded status was $18 million and $11 million as of December 31, 2019 and 2018, respectively.