CONSOLIDATED BALANCE SHEETS (Parenthetical) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Total cash, cash equivalents, and marketable securities, securities loaned	$ 0	$ 4,531
Accounts receivable, allowance	$ 467	$ 296
Convertible preferred stock, par value per share (in dollars per share)	$ 0.001	$ 0.001
Convertible preferred stock, shares authorized (in shares)	100,000,000	100,000,000
Convertible preferred stock, shares issued (in shares)	0	0
Convertible preferred stock, shares outstanding (in shares)	0	0
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock and capital stock, shares authorized (in shares)	15,000,000,000	15,000,000,000
Common stock, shares issued (in shares)	691,293,000	687,348,000
Common stock, shares outstanding (in shares)	691,293,000	687,348,000
Class A Common Stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock and capital stock, shares authorized (in shares)	9,000,000,000	9,000,000,000
Common stock, shares issued (in shares)	296,992,000	292,297,000
Common stock, shares outstanding (in shares)	296,992,000	292,297,000
Class B Common Stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock and capital stock, shares authorized (in shares)	3,000,000,000	3,000,000,000
Common stock, shares issued (in shares)	47,437,000	50,295,000
Common stock, shares outstanding (in shares)	47,437,000	50,295,000
Class C Capital Stock
Common stock, par value (in dollars per share)	$ 0.001	$ 0.001
Common stock and capital stock, shares authorized (in shares)	3,000,000,000	3,000,000,000
Common stock, shares issued (in shares)	346,864,000	344,756,000
Common stock, shares outstanding (in shares)	346,864,000	344,756,000