Revenues and Contract Costs - Schedule of Receivables from Contracts with Customers (Details) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020	Jan. 01, 2020
Revenue from Contract with Customer [Abstract]
Receivables	$ 10,758	$ 12,029	$ 12,078
Device payment plan agreement receivables	$ 12,888	$ 10,358	$ 11,741