Net Income (Loss) Per Share (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2021	Mar. 31, 2020
NUMERATOR:
Net income (loss)	$ 116	$ (94)
DENOMINATOR:
Weighted-average shares outstanding, basic	591	515
Dilutive effects of convertible notes	16	0	[1]
Dilutive effect of stock warrants	1	0
Dilutive effect of restricted stock units	1	0
Adjusted weighted-average shares outstanding, diluted	609	515
NET INCOME (LOSS) PER SHARE:
Basic	$ 0.20	$ (0.18)
Diluted	0.19	$ (0.18)
Debt Instrument, Convertible, Conversion Price	$ 38.48

[1] Because the Company intends to settle conversions by paying cash up to the principal amount of the convertible notes, with any excess conversion value settled in shares of common stock, the convertible notes are being accounted for using the treasury stock method for the purposes of Net income (loss) per share. Using this method, the denominator will be affected when the average share price of the Company's common stock for a given period is greater than the conversion price of approximately $38.48 per share, and the Company reports Net income for the given period. For the three months ended March 31, 2021, the average market price of the Company's common stock exceeded this conversion price per share and as such, the common shares underlying the convertible notes were included in the diluted calculation. See Note 8 for further information on the convertible notes.