Other Financial Data - Schedule of Other Current Liabilities (Details) - USD ($) $ in Millions	3 Months Ended	12 Months Ended
Mar. 31, 2019	Dec. 31, 2018
Other Financial Data [Abstract]
Deferred revenue	$ 305	$ 251
Leases	241
Taxes payable	158	83
Other	516	602
Total	1,220	936
Revenue recognized from deferred revenue	$ 134	$ 487

Operating Lease And Finance Lease Liability, Current

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Other Financial Data [Abstract]

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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 revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

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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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Amount of liabilities classified as other, due within one year or the normal operating cycle, if longer.

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