Revenue from Contracts with Customers - Concentration Risk (Details) - CenturyLink - Customer Concentration Risk	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Percentage of Accounts Receivable
Concentration Risk [Line Items]
Concentration of credit risk, percentage	17.00%	16.00%
Percentage of Revenue
Concentration Risk [Line Items]
Concentration of credit risk, percentage	15.00%	18.00%	31.00%

For an entity that discloses a concentration risk in relation to quantitative amount, which serves as the "benchmark" (or denominator) in the equation, this concept represents the concentration percentage derived from the division.

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