Summary of Significant Accounting Policies - Narrative (Details) connection in Millions, $ in Millions	12 Months Ended
	Dec. 31, 2023 USD ($) asset_group unit connection segment	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	May 04, 1988
Basis of presentation
Number of connections | connection	4.6
Number of reportable segments | segment	1
FCC Licenses, period of renewal	12 years
FCC Licenses, number of accounting units | unit	1
Asset groups | asset_group	1
Agent liability	$ 50	$ 53
Advertising costs	181	171	$ 184
Expenses related to strategic alternatives review	8
Amortization of implementation costs	$ 17	18	16
Minimum
Basis of presentation
FCC Licenses, period of renewal	10 years
Amortization period	3 years
Maximum
Basis of presentation
FCC Licenses, period of renewal	15 years
Amortization period	5 years
Leasehold and land improvements | Minimum
Basis of presentation
Useful life	1 year
Leasehold and land improvements | Maximum
Basis of presentation
Useful life	30 years
Pension
Basis of presentation
Defined contribution cost	$ 11	12	12
401(k)
Basis of presentation
Defined contribution cost	15	15	$ 15
TDS
Basis of presentation
Income taxes receivable	$ 0	$ 0
UScellular | TDS
Basis of presentation
TDS ownership of UScellular	83.00%
UScellular | TDS | Minimum
Basis of presentation
TDS ownership of UScellular				90.00%