Income Taxes - Schedule of Deferred Tax Assets and Liabilities (Details) - USD ($) $ in Millions	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Deferred tax assets:
Deferred and stock-based compensation	$ 89	$ 105
Pension	12	16
Liability reserve	35	37
Tax credits	3	12
Loss carryforward	138	147
Deferred revenue	24	24
Other	55	42
Total	356	383
Valuation allowance	(119)	(126)	$ (122)	$ (72)
Total deferred tax assets, net of valuation allowance	237	257
Deferred tax liabilities:
Property and equipment	(133)	(99)
Acquired intangibles	(2,439)	(2,453)
Total deferred tax liabilities	(2,572)	(2,552)
Net deferred tax liabilities	(2,335)	(2,295)
Reported as:
Net non-current deferred tax assets	2	3
Net non-current deferred tax liabilities	$ (2,337)	$ (2,298)