Revenues and Contract Costs - Additional Information (Details)	3 Months Ended
	Mar. 31, 2020 USD ($) segment	Mar. 31, 2019 USD ($)
Disaggregation of Revenue [Line Items]
Number of reportable segments | segment	2
Revenues from leasing arrangements, captive reinsurance arrangements and interest on equipment financed	$ 812,000,000	$ 787,000,000
Contract description of timing	Contracts for wireless services are generally either month-to-month and cancellable at any time (typically under a device payment plan) or contain terms ranging from greater than one month to up to two years (typically under a fixed-term plan).
Amortization of deferred contract costs	$ 778,000,000	615,000,000
Contract assets impairment charge	0	0
Media Business
Disaggregation of Revenue [Line Items]
Revenue from contract with customer	$ 1,700,000,000	$ 1,800,000,000
Wireless postpaid contracts
Disaggregation of Revenue [Line Items]
Percentage of month-to-month contracts of total service contracts	88.00%	86.00%
Wireline Consumer and Small and Medium Business contracts
Disaggregation of Revenue [Line Items]
Percentage of month-to-month contracts of total service contracts	64.00%	55.00%
Reseller Arrangements
Disaggregation of Revenue [Line Items]
Contract description of timing	Reseller arrangements generally include a stated contract term, which typically extends longer than two years and, in some cases, include a periodic minimum revenue commitment over the contract term for which revenues will be recognized in future periods.
Consumer
Disaggregation of Revenue [Line Items]
Customer contracts service term	2 years
Business
Disaggregation of Revenue [Line Items]
Contract description of timing	These contracts have varying terms spanning over approximately five years
Maximum | Business
Disaggregation of Revenue [Line Items]
Customer contracts service term	12 months