Revenues and Contract Costs - Additional Information (Details)	3 Months Ended
	Mar. 31, 2025 USD ($) segment	Mar. 31, 2024 USD ($)
Disaggregation of Revenue [Line Items]
Number of reportable segments | segment	2
Revenue recognized related to contract liabilities existing	$ 4,600,000,000	$ 4,400,000,000
Amortization of deferred contract costs	877,000,000	829,000,000
Contract assets impairment charge	$ 0	$ 0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-04-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	36 months
Revenue, remaining performance obligation	$ 53,300,000,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2028-04-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period
Wireless postpaid contracts
Disaggregation of Revenue [Line Items]
Percentage of month-to-month contracts of total service contracts	95.00%	95.00%
Wireline Consumer And Business Markets And Other Contracts
Disaggregation of Revenue [Line Items]
Percentage of month-to-month contracts of total service contracts	95.00%	94.00%
Customer Contracts that Have Contract Minimum over Total Contract Term | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-04-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	28 years
Revenue, remaining performance obligation	$ 1,600,000,000
Minimum
Disaggregation of Revenue [Line Items]
Deferred contract cost, amortization period	2 years
Minimum | Wireless Service, Device Payment Plan and Fixed-Term Plan
Disaggregation of Revenue [Line Items]
Customer contracts service term	1 month
Minimum | Consumer
Disaggregation of Revenue [Line Items]
Customer contracts service term	12 months
Minimum | Consumer | Reseller Arrangements
Disaggregation of Revenue [Line Items]
Customer contracts service term	2 years
Maximum
Disaggregation of Revenue [Line Items]
Deferred contract cost, amortization period	7 years
Maximum | Wireless Service, Device Payment Plan and Fixed-Term Plan
Disaggregation of Revenue [Line Items]
Customer contracts service term	36 months
Maximum | Consumer
Disaggregation of Revenue [Line Items]
Customer contracts service term	2 years
Maximum | Business
Disaggregation of Revenue [Line Items]
Customer contracts service term	12 months