Discontinued Operations Narrative (Details) $ in Millions		3 Months Ended		6 Months Ended		10 Months Ended
	Mar. 05, 2017 USD ($) day	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Jun. 30, 2017 USD ($)	Jun. 30, 2016 USD ($)	Dec. 31, 2017 USD ($)
Line of Credit [Member] | Revolving Credit Facility [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Debt term				3 years
Opel/Vauxhall Business and Fincos [Member] | Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Estimated net consideration for transferred business	$ 2,200
Opel/Vauxhall Business and Fincos [Member] | Discontinued Operations [Member] | Forecast [Member] | Minimum [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Expected charge at closing						$ 5,500
Opel/Vauxhall Business and Fincos [Member] | Discontinued Operations [Member] | Forecast [Member] | Maximum [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Expected charge at closing						6,000
Opel/Vauxhall Business [Member] | Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Estimated net consideration for transferred business	1,200
Cash received from sale	1,000
Warrants received	700
De-risking premium payment and deferred pension losses	$ 500
Warrant vesting period	5 years
Threshold to sell the warrants after exercise (in days) | day	35
Other costs and charges		$ 421
Total net sales and revenue transactions with discontinued operations		760	$ 570	$ 1,500	$ 1,200
Total costs and expenses transactions with discontinued operations		713	$ 512	$ 1,400	$ 1,000
Opel/Vauxhall Business [Member] | Discontinued Operations [Member] | Forecast [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
De-risking premium payment and deferred pension losses						1,600
Charge for deferred tax assets no longer realizable upon transfer						3,900
Underfunded pension liabilities of retired and former employees						7,000
Underfunded pension liabilities of current employees						2,900
Payment to PSA Group at closing						3,400
Fincos [Member] | Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Estimated net consideration for transferred business	$ 1,000
Percent of book value received	80.00%
Disposal loss		$ 324
Fincos [Member] | Discontinued Operations [Member] | Forecast [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Disposal loss						$ 700