Acquisitions - Purchase Price Allocation (Details) - USD ($) $ in Millions		1 Months Ended	12 Months Ended
	Dec. 23, 2016	Feb. 28, 2011	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Business Acquisition [Line Items]
Purchase price, cash consideration			$ 78
Business Combination, Goodwill			$ 90	$ 80	$ 90
SIFCO S.A. [Member]
Business Acquisition [Line Items]
Purchase price, cash consideration	$ 60	$ 150
Purchase price, deferred consideration	9
Total purchase consideration	69
Business Combination, Accounts receivable - Trade	1
Business Combination, Accounts receivable - Other	1
Business Combination, Inventories	10
Business Combination, Goodwill	6
Business Combination, Intangibles	3
Business Combination, Property, plant and equipment	59
Business Combination, Accounts payable	(2)
Business Combination, Accrued payroll and employee benefits	(9)
Business Combination, Total purchase consideration allocation	$ 69