Other Financial Data - Schedule of Other Non-current Assets (Details) - USD ($) $ in Millions	Jun. 30, 2019	Dec. 31, 2018
Other Financial Data [Abstract]
Cost to obtain contracts with customers	$ 161	$ 156
Taxes receivable	100	100
Finance lease assets	65
Investments	54	54
Other	141	138
Total	$ 521	$ 448

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.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 606
-SubTopic 10
-Section 45
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- Definition

Amount of lessee's right to use underlying asset under finance lease.

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Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 842
-SubTopic 20
-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.

+ References

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-SubTopic 10
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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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