Amount before tax of gain (loss) not previously recognized resulting from the disposal of a discontinued operation.

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Discontinued Operations - Narrative (Details) - USD ($) $ in Millions		2 Months Ended	3 Months Ended			12 Months Ended
	Oct. 31, 2017	Dec. 31, 2017	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Payments of dividends						$ 434	$ 550	$ 0
Special Dividend [Member] \| GM [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Payments of dividends		$ 550
European Operations [Member] \| Discontinued Operations [Member]
Income Statement, Balance Sheet and Additional Disclosures by Disposal Groups, Including Discontinued Operations [Line Items]
Consideration received	$ 1,100
Loss on sale of discontinued operations before income taxes	525		$ 151	$ 38	$ 336
Foreign currency translation losses	$ 197