Accounts Receivable, Net (Schedule of Receivables, Net) (Details) - USD ($) $ in Millions	Sep. 30, 2021	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019
Receivables [Abstract]
Accounts receivable	$ 10,033	$ 9,800
Allowance for expected credit losses	(495)	(546)	$ (530)	$ (254)
Total accounts receivable, net	$ 9,538	$ 9,254