Wireless Licenses, Goodwill and Other Intangible Assets - Composition of Other Intangible Assets, Net (Detail) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2023	Dec. 31, 2022
Finite-Lived Intangible Assets [Line Items]
Gross Amount	$ 30,990	$ 30,562
Accumulated Amortization	(19,744)	(19,101)
Net Amount	11,246	11,461
Customer Lists
Finite-Lived Intangible Assets [Line Items]
Gross Amount	4,335	4,335
Accumulated Amortization	(1,776)	(1,646)
Net Amount	$ 2,559	2,689
Customer Lists | Minimum
Finite-Lived Intangible Assets [Line Items]
Other intangible asset, useful life	5 years
Customer Lists | Maximum
Finite-Lived Intangible Assets [Line Items]
Other intangible asset, useful life	13 years
Non-Network Internal-Use Software
Finite-Lived Intangible Assets [Line Items]
Other intangible asset, useful life	7 years
Gross Amount	$ 23,838	23,421
Accumulated Amortization	(16,835)	(16,397)
Net Amount	7,003	7,024
Other
Finite-Lived Intangible Assets [Line Items]
Gross Amount	2,817	2,806
Accumulated Amortization	(1,133)	(1,058)
Net Amount	$ 1,684	$ 1,748
Other | Minimum
Finite-Lived Intangible Assets [Line Items]
Other intangible asset, useful life	4 years
Other | Maximum
Finite-Lived Intangible Assets [Line Items]
Other intangible asset, useful life	25 years