Revenue Recognition - Disaggregation of Revenue (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Disaggregation of revenue
Revenue from contracts with customers	$ 1,230	$ 1,272
Operating lease income	32	31
Total operating revenues	1,262	1,303
Transferred over time
Disaggregation of revenue
Revenue from contracts with customers	1,012	1,012
Transferred over time | Retail service
Disaggregation of revenue
Revenue from contracts with customers	678	691
Transferred over time | Residential
Disaggregation of revenue
Revenue from contracts with customers	185	169
Transferred over time | Commercial
Disaggregation of revenue
Revenue from contracts with customers	37	41
Transferred over time | Wholesale
Disaggregation of revenue
Revenue from contracts with customers	43	42
Transferred over time | Other service
Disaggregation of revenue
Revenue from contracts with customers	69	69
Transferred at point in time | Equipment and product sales
Disaggregation of revenue
Revenue from contracts with customers	218	260
UScellular
Disaggregation of revenue
Revenue from contracts with customers	925	961
Operating lease income	25	25
Total operating revenues	950	986
UScellular | Transferred over time
Disaggregation of revenue
Revenue from contracts with customers	729	742
UScellular | Transferred over time | Retail service
Disaggregation of revenue
Revenue from contracts with customers	678	691
UScellular | Transferred over time | Residential
Disaggregation of revenue
Revenue from contracts with customers	0	0
UScellular | Transferred over time | Commercial
Disaggregation of revenue
Revenue from contracts with customers	0	0
UScellular | Transferred over time | Wholesale
Disaggregation of revenue
Revenue from contracts with customers	0	0
UScellular | Transferred over time | Other service
Disaggregation of revenue
Revenue from contracts with customers	51	51
UScellular | Transferred at point in time | Equipment and product sales
Disaggregation of revenue
Revenue from contracts with customers	196	219
TDS Telecom
Disaggregation of revenue
Revenue from contracts with customers	266	252
Operating lease income	1	1
Total operating revenues	266	253
TDS Telecom | Transferred over time
Disaggregation of revenue
Revenue from contracts with customers	265	252
TDS Telecom | Transferred over time | Retail service
Disaggregation of revenue
Revenue from contracts with customers	0	0
TDS Telecom | Transferred over time | Residential
Disaggregation of revenue
Revenue from contracts with customers	185	169
TDS Telecom | Transferred over time | Commercial
Disaggregation of revenue
Revenue from contracts with customers	37	41
TDS Telecom | Transferred over time | Wholesale
Disaggregation of revenue
Revenue from contracts with customers	43	42
TDS Telecom | Transferred over time | Other service
Disaggregation of revenue
Revenue from contracts with customers	0	0
TDS Telecom | Transferred at point in time | Equipment and product sales
Disaggregation of revenue
Revenue from contracts with customers	0	0
Corporate, Eliminations and Other
Disaggregation of revenue
Revenue from contracts with customers	40	59
Operating lease income	6	5
Total operating revenues	46	64
Corporate, Eliminations and Other | Transferred over time
Disaggregation of revenue
Revenue from contracts with customers	18	18
Corporate, Eliminations and Other | Transferred over time | Retail service
Disaggregation of revenue
Revenue from contracts with customers	0	0
Corporate, Eliminations and Other | Transferred over time | Residential
Disaggregation of revenue
Revenue from contracts with customers	0	0
Corporate, Eliminations and Other | Transferred over time | Commercial
Disaggregation of revenue
Revenue from contracts with customers	0	0
Corporate, Eliminations and Other | Transferred over time | Wholesale
Disaggregation of revenue
Revenue from contracts with customers	0	0
Corporate, Eliminations and Other | Transferred over time | Other service
Disaggregation of revenue
Revenue from contracts with customers	18	18
Corporate, Eliminations and Other | Transferred at point in time | Equipment and product sales
Disaggregation of revenue
Revenue from contracts with customers	$ 22	$ 41