Products and Services Revenues - Revenue From Products and Services (Details) $ in Millions	2 Months Ended	3 Months Ended								10 Months Ended	12 Months Ended
	Dec. 31, 2017 USD ($)	Dec. 31, 2019 USD ($)	Sep. 30, 2019 USD ($)	Jun. 30, 2019 USD ($)	Mar. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Sep. 30, 2018 USD ($)	Jun. 30, 2018 USD ($)	Mar. 31, 2018 USD ($)	Oct. 31, 2017 USD ($)	Dec. 31, 2019 USD ($) segment	Dec. 31, 2018 USD ($)
Revenue from External Customer [Line Items]
Total operating revenue	$ 1,407	$ 2,061	$ 2,064	$ 2,014	$ 2,046	$ 2,071	$ 2,010	$ 2,052	$ 2,087	$ 6,870	$ 8,185	$ 8,220
USF contributions	$ 71									$ 331	$ 428	$ 415
Number of reportable segments | segment											1
Customer Concentration Risk | Sales Revenue
Revenue from External Customer [Line Items]
Concentration risk, percentage	19.00%									18.00%	16.00%	20.00%
IP and Data Services
Revenue from External Customer [Line Items]
Total operating revenue	$ 668									$ 3,284	$ 3,888	$ 3,945
Transport and Infrastructure
Revenue from External Customer [Line Items]
Total operating revenue	464									2,272	2,662	2,701
Voice and Collaboration
Revenue from External Customer [Line Items]
Total operating revenue	258									1,308	1,443	1,464
Other revenue
Revenue from External Customer [Line Items]
Total operating revenue	1									6	12	3
Affiliate revenue
Revenue from External Customer [Line Items]
Total operating revenue	$ 16									$ 0	$ 180	$ 107