Segment Information - Segment Results and Operating Revenue (Details ) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Operating revenues by products and services
Revenues	$ 14,557	$ 17,478	$ 19,687
Cost of services and products	7,144	7,868	8,488
Selling, general and administrative	3,198	3,078	2,895
Business
Operating revenues by products and services
Revenues	11,535	13,041	14,119
Cost of services and products	3,138	3,257	3,488
Selling, general and administrative	1,232	1,215
Selling, general and administrative			1,273
Total expense	4,370	4,472	4,761
Total segment adjusted EBITDA	7,165	8,569	9,358
Mass Markets
Operating revenues by products and services
Revenues	3,022	4,437	5,568
Cost of services and products	92	124	153
Selling, general and administrative	1,341	1,623
Selling, general and administrative			1,685
Total expense	1,433	1,747	1,838
Total segment adjusted EBITDA	$ 1,589	$ 2,690	$ 3,730