Significant Accounting Policies - Future Minimum Commitments Under Our corporate Headquarters Lease and Other Non-Cancelable Operating Leases (Parenthetical) (Details) $ in Millions	Dec. 31, 2018 USD ($)
Accounting Policies [Abstract]
Other long-term liabilities under financial obligation	$ 83	[1]

[1] Refer to “Note 2: Significant Accounting Policies” for additional information on our lease information, including transition accounting and updated accounting policy for leases upon adoption of ASC 842.