Consolidated Statements of Operations (Parenthetical) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Income (loss) from operations of discontinued businesses, income tax benefit (expense)	$ 0	$ (2)	$ (21)
Gain (loss) from disposal of discontinued businesses, income tax benefit (expense)	$ 0	$ (44)	$ 0

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

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