Accounts Receivable, Net - Narrative (Details) - USD ($) $ in Millions	Mar. 31, 2020	Jan. 01, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for receivables net current	$ 928		$ 778
Allowance for current expected credit losses	61	$ 39
Adjustment upon Adoption | ASU 2016-13
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for current expected credit losses
COVID-19
Accounts, Notes, Loans and Financing Receivable [Line Items]
Allowance for current expected credit losses	$ 13