Stockholders' Equity (Unvested Restricted Stock Units Activity) (Details) (Restricted Stock Units (RSUs), USD $)	6 Months Ended
	Jun. 30, 2014
Restricted Stock Units (RSUs)
Unvested restricted stock units - number of shares
Unvested as of December 31, 2013 (in shares)	21,953,960
Granted (in shares)	3,006,717
Vested (in shares)	(5,281,669)
Forfeited/canceled (in shares)	(607,200)
Unvested as of June 30, 2014 (in shares)	19,071,808
Expected to vest after June 30, 2014 (in shares)	16,725,976	[1]
Unvested restricted stock units - weighted-average grant-date fair value
Unvested as of December 31, 2013 (in dollars per share)	$ 359.20
Granted (in dollars per share)	$ 566.91
Vested (in dollars per share)	$ 325.14
Forfeited/canceled (in dollars per share)	$ 341.32
Unvested as of June 30, 2014 (in dollars per share)	$ 401.47
Expected to vest after June 30, 2014 (in dollars per share)	$ 401.47	[1]

[1] RSUs expected to vest reflect an estimated forfeiture rate.