Percentage of Completion Contracts (Details) - USD ($)		3 Months Ended			9 Months Ended
	May 26, 2016	Mar. 31, 2017	Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2016	Sep. 30, 2017
Billed and Unbilled Contract Claims Subject to Uncertainty [Line Items]
Billings in excess of cost						$ (47,000,000)
Contract settlement amount	$ 150,000,000
Proceeds from contract settlements		$ 16,000,000	$ 72,000,000	$ 62,000,000
Iraq
Billed and Unbilled Contract Claims Subject to Uncertainty [Line Items]
Total estimated loss on contracts			532,000,000		$ 532,000,000
Contract claims revenue					0
Deductions (back charges)			25,000,000		25,000,000
Accounts receivable, unapproved contract claims			$ 25,000,000		$ 25,000,000