Sales of Certain Receivables - Sales of EIP Receivables (Details) - USD ($) $ in Millions	Mar. 31, 2022	Dec. 31, 2021
Variable Interest Entity [Line Items]
Other current assets	$ 1,691	$ 2,005
Other assets	6,276	3,232
EIP Securitization Arrangement
Variable Interest Entity [Line Items]
Revolving receivables facility, maximum borrowing capacity	1,300	1,300
Other current assets	382	424
Other assets	108	125
Other long-term liabilities	$ 2	$ 0