Stockholders' Equity - Common Stock (Details) - $ / shares	Mar. 31, 2020	Dec. 31, 2019	Feb. 01, 2019
Business Acquisition [Line Items]
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock, shares authorized (in shares)	9,000,000,000	9,000,000,000
Common stock, shares issued (in shares)	4,379,000,000	4,412,000,000
Common stock, shares outstanding (in shares)	4,379,000,000	4,412,000,000
Common stock reserved for issuance (in shares)	274,000,000
Pandora
Business Acquisition [Line Items]
Common stock, par value (in dollars per share)			$ 0.001