Segment Information - Segment Results and Operating Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Mar. 31, 2022
Operating revenues by products and services
Segment revenue	$ 3,738	$ 4,676
Cost of services and products	1,817	1,985
Selling, general and administrative	721	800
Total Adjusted EBITDA	1,137	1,914
Operating Segments
Operating revenues by products and services
Segment revenue	3,738	4,676
Operating Segments | Business
Operating revenues by products and services
Segment revenue	2,956	3,401
Cost of services and products	801	812
Selling, general and administrative	290	322
Total segment expense	1,091	1,134
Total Adjusted EBITDA	1,865	2,267
Operating Segments | Mass Markets
Operating revenues by products and services
Segment revenue	782	1,275
Cost of services and products	25	32
Selling, general and administrative	325	395
Total segment expense	350	427
Total Adjusted EBITDA	432	848
Segment Reconciling Items
Operating revenues by products and services
Total Adjusted EBITDA	$ (1,160)	$ (1,201)