Revenue and Contract Costs - Narrative (Details)	12 Months Ended
	Dec. 31, 2023 USD ($) segment	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)
Disaggregation of Revenue [Line Items]
Number of reportable segments | segment	2
Revenue from arrangements not accounted for under Topic 606	$ 2,900,000,000	$ 3,200,000,000	$ 3,100,000,000
Contract with customer liability period increase	668,000,000
Revenue recognized from previously recognized contract liability	4,900,000,000	5,000,000,000
Amortization of deferred contract costs	3,200,000,000	3,000,000,000
Deferred contract costs, impairment charges	$ 0	$ 0
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, remaining performance obligation	$ 25,700,000,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2025-01-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	1 year
Revenue, remaining performance obligation	$ 18,700,000,000
Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2026-01-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period
Revenue, remaining performance obligation	$ 7,500,000,000
Minimum
Disaggregation of Revenue [Line Items]
Deferred contract cost, amortization period	1 year
Minimum | Consumer
Disaggregation of Revenue [Line Items]
Contract term	12 months
Maximum
Disaggregation of Revenue [Line Items]
Deferred contract cost, amortization period	7 years
Maximum | Consumer
Disaggregation of Revenue [Line Items]
Contract term	2 years
Maximum | Business
Disaggregation of Revenue [Line Items]
Contract term	12 months
Wireless postpaid contracts
Disaggregation of Revenue [Line Items]
Percentage of month-to-month contracts of total service contracts	95.00%	94.00%
Wireline Consumer And Business Markets And Other Contracts
Disaggregation of Revenue [Line Items]
Percentage of month-to-month contracts of total service contracts	94.00%	92.00%
Wireless Service, Device Payment Plans | Minimum
Disaggregation of Revenue [Line Items]
Contract term	1 month
Wireless Service, Device Payment Plans | Maximum
Disaggregation of Revenue [Line Items]
Contract term	36 months
Wireless Service, Fixed Term Plans | Minimum
Disaggregation of Revenue [Line Items]
Contract term	1 month
Wireless Service, Fixed Term Plans | Maximum
Disaggregation of Revenue [Line Items]
Contract term	24 months
Reseller Arrangements | Minimum | Consumer
Disaggregation of Revenue [Line Items]
Contract term	2 years
Customer Contracts that Have Contract Minimum over Total Contract Term | Revenue, Remaining Performance Obligation, Expected Timing of Satisfaction, Start Date [Axis]: 2024-01-01
Disaggregation of Revenue [Line Items]
Revenue, remaining performance obligation, expected timing of satisfaction, period	30 years
Revenue, remaining performance obligation	$ 2,100,000,000