Taxes - Schedule of Deferred Taxes (Detail) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Deferred Tax Assets
Employee benefits	$ 4,388	$ 5,218
Tax loss and credit carry forwards	2,224	2,848
Other - assets	7,314	6,096
Deferred tax assets, gross	13,926	14,162
Valuation allowances	(1,574)	(2,183)
Deferred tax assets	12,352	11,979
Deferred Tax Liabilities
Spectrum and other intangible amortization	24,935	22,726
Depreciation	19,893	18,009
Other - liabilities	8,041	6,867
Deferred tax liabilities	52,869	47,602
Net deferred tax liability	$ 40,517	$ 35,623