CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Mar. 31, 2020	Dec. 31, 2019
Accounts receivable, allowance	$ 95	$ 41
Treasury stock - Common stock, Shares	130,592,000	126,893,000
Common stock
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, Authorized shares	1,600,000,000	1,600,000,000
Common stock, Shares issued	258,770,000	256,692,000
Common stock, Shares outstanding	135,454,000	137,076,000
Class B Common Stock
Common stock, par value (in dollars per share)	$ 0.0001	$ 0.0001
Common stock, Authorized shares	400,000,000	400,000,000
Common stock, Shares issued	12,800,000	12,800,000
Common stock, Shares outstanding	5,523,000	5,523,000
Treasury stock - Common stock, Shares	7,300,000	7,300,000