Products and Services Revenue - Operating Revenues for Products and Services (Details) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2020	Mar. 31, 2019
Disaggregation of Revenue [Line Items]
Operating revenues	[1]	$ 1,918	$ 2,030
IP and Data Services
Disaggregation of Revenue [Line Items]
Operating revenues		136	140
Transport and Infrastructure
Disaggregation of Revenue [Line Items]
Operating revenues		657	701
Voice and Collaboration
Disaggregation of Revenue [Line Items]
Operating revenues		395	418
IT and Managed Services
Disaggregation of Revenue [Line Items]
Operating revenues		1	1
Regulatory Revenue
Disaggregation of Revenue [Line Items]
Operating revenues		46	48
Affiliate Services
Disaggregation of Revenue [Line Items]
Operating revenues		$ 683	$ 722

[1] Reclassifications were made within certain 2019 comparative figures due to the retrospective application of an accounting policy election during the first quarter of 2020. Refer to Note 1—Background and our Form 8-K filing dated May 7, 2020 for further information.