Income Taxes - Deferred Income Tax (Details) - USD ($) $ in Millions	Dec. 31, 2016	Dec. 31, 2015
Deferred Tax Assets, Gross [Abstract]
Net operating and credit carryforwards	$ 117	$ 1
Other accrued liabilities	101	2
Accrued stock compensation	175
Other	280	2
Deferred tax assets	673	5
Valuation allowance	(66)	(1)
Net deferred tax assets	607	4
Deferred Tax Liabilities, Gross [Abstract]
Investments		292
Intangible assets	3,909	15
Other	175	1
Deferred tax liabilities	4,084	308
Net deferred tax liabilities	$ 3,477	$ 304