Accounts Receivable - Schedule in Accounts Receivable (Details) - USD ($) $ in Millions	Dec. 31, 2020	Dec. 31, 2019
Accounts, Notes, Loans and Financing Receivable [Line Items]
Other receivables	$ 91	$ 20
Total accounts receivable	2,153	2,365
Less: allowance for credit losses	(191)	(106)
Accounts receivable, less allowance	1,962	2,259
Earned and unbilled receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	345	374
Trade and purchased receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	$ 1,717	$ 1,971