Revenue Recognition (Disaggregation Of Revenue) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Jun. 30, 2025	Jun. 30, 2024	Jun. 30, 2025	Jun. 30, 2024
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 1,522	$ 1,466	$ 3,017	$ 2,912
Subsidy and other revenue	17	14	33	30
Total revenue	1,539	1,480	3,050	2,942
Lease revenue	13	14	26	27
Revenue from contracts with customers, performance obligation	1,147		1,147
Data And Internet Services [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	1,085	983	2,134	1,930
Voice Services [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	282	312	572	633
Video Services [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	68	88	142	182
Other [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	87	83	169	167
Consumer [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	825	789	1,638	1,576
Business And Wholesale [Member]
Disaggregation of Revenue [Line Items]
Revenue from contracts with customers	$ 697	$ 677	$ 1,379	$ 1,336