Other Financial Data - Schedule of Other Non-current Assets (Details) - USD ($) $ in Millions	Jun. 30, 2018	Jan. 01, 2018	Dec. 31, 2017
Other Financial Data [Abstract]
Investments	$ 54		$ 57
Taxes receivable	77		84
Cost to obtain contracts with customers	144		0
Other	129		166
Total	$ 404	$ 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
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
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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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