Acquisitions and Divestitures - Assets Held for Sale (Details) - USD ($) $ in Millions	12 Months Ended
	Sep. 30, 2018	Dec. 31, 2018
Assets held for sale | Detroit Properties and Airplanes
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset impairment charge	$ 49
Assets held for sale | Corporate-related | Detroit Properties and Airplanes
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset impairment charge	10
Assets held for sale | Seating | Detroit Properties and Airplanes
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Asset impairment charge	39
Disposed of by sale | Detroit Airplane
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration for disposal group	$ 36
Disposed of by sale | Detroit Properties and Airplane
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration for disposal group		$ 35