Accounts Receivable - Schedule of Accounts Receivable (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	$ 680	$ 723
Less: allowance for doubtful accounts	(13)	(11)
Accounts receivable, less allowance	667	712
Trade receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	529	533
Earned and unbilled receivables
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	151	177
Other
Accounts, Notes, Loans and Financing Receivable [Line Items]
Total accounts receivable	$ 0	$ 13