Summary of Significant Accounting Policies - Schedule of Computation of Basic and Diluted Net Income (Loss) Per Sale of Common Stock Attributable to Common Stockholders (Detail) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019
Net income (loss) per share of common stock attributable to common stockholders, basic
Net income (loss) attributable to common stockholders	$ 16	$ (702)
Less: Buy-out of noncontrolling interest		8
Net income (loss) used in computing net income (loss) per share of common stock, basic	$ 16	$ (710)
Weighted average shares used in computing net income (loss) per share of common stock, basic	183	173
Net income (loss) per share of common stock attributable to common stockholders, basic	$ 0.09	$ (4.10)
Net income (loss) per share of common stock attributable to common stockholders, diluted
Net income (loss) attributable to common stockholders	$ 16	$ (702)
Less: Buy-out of noncontrolling interest		8
Net income (loss) used in computing net income (loss) per share of common stock, diluted	$ 16	$ (710)
Weighted average shares used in computing net income (loss) per share of common stock, basic	183	173
Stock-based awards	9
Convertible senior notes	6
Warrants	1
Weighted average shares used in computing net income (loss) per share of common stock, diluted	199	173
Net income (loss) per share of common stock attributable to common stockholders, diluted	$ 0.08	$ (4.10)