Products and Services Revenue - Operating Revenues for Products and Services (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Mar. 31, 2018
Disaggregation of Revenue [Line Items]
Operating revenues	$ 2,055	$ 2,130
IP & Data Services
Disaggregation of Revenue [Line Items]
Operating revenues	147	150
Transport & Infrastructure
Disaggregation of Revenue [Line Items]
Operating revenues	715	744
Voice & Collaboration
Disaggregation of Revenue [Line Items]
Operating revenues	422	467
IT & Managed Services
Disaggregation of Revenue [Line Items]
Operating revenues	1	2
Regulatory Revenue
Disaggregation of Revenue [Line Items]
Operating revenues	48	56
Affiliate Services
Disaggregation of Revenue [Line Items]
Operating revenues	$ 722	$ 711