Claims and Accounts Receivable (Details) - USD ($) $ in Millions	Dec. 31, 2019	Dec. 31, 2018
Accounts, Notes, Loans and Financing Receivable [Line Items]
Claims receivable	$ 59	$ 98
Government Services
Accounts, Notes, Loans and Financing Receivable [Line Items]
Government contract receivable	28	73
Claims and uncertain amounts	$ 31	$ 25