Other Financial Data - Schedule of Other Non-current Assets (Details) - USD ($) $ in Millions	Sep. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Other Financial Data [Abstract]
Cost to obtain contracts with customers	$ 150		$ 0
Investments	52		57
Taxes receivable	75		84
Other	157		166
Total	$ 434	$ 452	$ 307

Other Financial Data [Abstract]

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- Definition

Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time, classified as noncurrent.

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-Publisher FASB
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-Topic 606
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Carrying amount due after one year of the balance sheet date (or one operating cycle, if longer) from tax authorities as of the balance sheet date representing refunds of overpayments or recoveries based on agreed-upon resolutions of disputes.

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-Publisher FASB
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-SubTopic 10
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- Definition

The total amount of investments that are intended to be held for an extended period of time (longer than one operating cycle).

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- Definition

Amount of other miscellaneous assets expected to be realized or consumed after one year or normal operating cycle, if longer.

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Amount of noncurrent assets classified as other.

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