Income Taxes - Components of Net Deferred Tax Assets (Liabilities) (Details) - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016
Deferred tax assets:
Allowance for sales returns and price protection	$ 47	$ 64
Inventory reserve	5	9
Accrued expenses	26	25
Deferred revenue	245	233
Tax credit carryforwards	60	48
Net operating loss carryforwards	11	10
Share-based compensation	59	61
Acquired intangibles	149	111
State taxes	22	24
Other	39	28
Deferred tax assets	663	613
Valuation allowance	0	0
Deferred tax assets, net of valuation allowance	663	613
Deferred tax liabilities:
Acquired intangibles	(146)	(219)
Prepaid royalties	(19)	(60)
Capitalized software development expenses	(55)	(91)
Other	(5)	(4)
Deferred tax liabilities	(225)	(374)
Net deferred tax assets	$ 438	$ 239