Percentage of Completion Contracts (Details) - USD ($) $ in Millions		3 Months Ended				9 Months Ended
	May 26, 2016	Mar. 31, 2017	Sep. 30, 2016	Jun. 30, 2016	Sep. 30, 2015	Sep. 30, 2015
Billed and Unbilled Contract Claims Subject to Uncertainty [Line Items]
Litigation Settlement, Amount	$ 150					$ (112)
Proceeds from Legal Settlements			$ 72	$ 62
Billings in Excess of Cost			(46)
Scenario, Forecast
Billed and Unbilled Contract Claims Subject to Uncertainty [Line Items]
Proceeds from Legal Settlements		$ 16
IRAQ
Billed and Unbilled Contract Claims Subject to Uncertainty [Line Items]
Loss on Contracts					$ 44	71
Total Estimated Loss on Contracts			532		450	450
Accounts Receivable, Unapproved Contract Claims			25		144	144
Deductions (Back Charges)			$ 25		21	21
Costs in Excess of Billings, Current					$ 93	$ 93