Accounts Receivable, Net (Schedule of Receivables, Net) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Receivables [Abstract]
Accounts Receivable, before Allowance for Credit Loss	$ 13,601	$ 13,913
Accounts Receivable, Allowance for Credit Loss	(497)	(389)
Accounts Receivable, after Allowance for Credit Loss	$ 13,104	$ 13,524