Amount before tax of gain (loss) recognized on the sale or disposal of a disposal group. Excludes discontinued operations.

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Difference between the fair value of payments made and the carrying amount of debt which is extinguished prior to maturity.

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Amount of impairment loss resulting from write-down of assets, excluding financial assets and goodwill, lacking physical substance and having a projected indefinite period of benefit to fair value.

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Amount of the difference between reported income tax expense (benefit) and expected income tax expense (benefit) computed by applying the domestic federal statutory income tax rates to pretax income (loss) from continuing operations, attributable to increase (decrease) in the income tax rates.

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Quarterly Results (Unaudited) - Additional Information (Details) - USD ($) $ in Millions			3 Months Ended				12 Months Ended
	Dec. 31, 2017	Apr. 04, 2017	Jun. 30, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Quarterly Financial Information Disclosure [Abstract]
Impairment of intangible asset used in research and development			$ 20				$ 20
Pre-tax charge to adjust carrying value of business held for sale			$ 3	$ (27)			3	$ (27)
Tax charge to recognize tax reform legislation	$ 186
Loss on extinguishment of debt		$ 6			$ 13	$ 6		$ 19	$ 17