Acquisitions and Divestitures Acquisitions and Divestitures, Assets Held for Sale (Details) - USD ($) $ in Millions	Mar. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Total assets classified as held for sale	$ 136		$ 135
Total liabilities classified as held for sale	19	$ 16	17
Assets Held for Sale [Member] | Aerostructures [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Billed receivables	13		14
Contract assets	33		0
Contracts in process	0		33
Prepaid expenses and other current assets	4		0
Total current assets	50		47
Property, plant and equipment, net	32		34
Goodwill	52		52
Identifiable intangible assets	2		2
Total assets classified as held for sale	136		135
Accounts payable, trade	7		3
Accrued employment costs	1		2
Accrued expenses	2		3
Other current liabilities	5		5
Total current liabilities	15		13
Deferred income taxes	$ 4		$ 4