Other Financial Data - Schedule of Other Current Liabilities (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2018	Sep. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Other Financial Data [Abstract]
Deferred revenue	$ 266	$ 266		$ 311
Taxes payable	16	16		139
Other	706	706		420
Total	988	988	$ 883	870
Revenue recognized from deferred revenue	$ 133	$ 348
Current portion of transition tax				$ 42

Other Financial Data [Abstract]

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Tax Cuts And Jobs Act Of 2017, Incomplete Accounting, Transition Tax For Accumulated Foreign Earnings, Provisional Liability, Current

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Carrying amount as of the balance sheet date of the unpaid sum of the known and estimated amounts payable to satisfy all currently due domestic and foreign income tax obligations.

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Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable, classified as current.

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Amount of expenses incurred but not yet paid classified as other, due within one year or the normal operating cycle, if longer.

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