Revenue Recognition - Reconciliation of Contract Balances (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2022	Dec. 31, 2021
Reconciliation of Contract Balances
Notes and accounts receivable - trade (net of allowances of $225 in 2022 and $218 in 2021)	$ 5,963	$ 6,754
Notes and accounts receivable - trade, allowances	225	218
Contract assets	517	471
Deferred income (current)	13,526	12,518
Deferred income (noncurrent)	3,423	$ 3,577
Revenue recognized that was included in deferred income at the beginning of the period	$ 4,000

Amount, after allowance for credit loss, of right to consideration from customer for product sold and service rendered in normal course of business, classified as current.

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