Property, Plant, and Equipment (Narative) (Details) $ in Millions	1 Months Ended	9 Months Ended
Nov. 30, 2018 USD ($) item	Sep. 30, 2018 USD ($)
Property, Plant and Equipment [Line Items]
Proceeds from sale of property		$ 11
Sale leaseback, gains		$ 9
Sale Leaseback Transaction, Deferred Gain, Amortization Period		2 years
Sale leaseback, gain recognized		$ 27
Sale leaseback, gain remaining		$ 25
Subsequent Event [Member]
Property, Plant and Equipment [Line Items]
Proceeds from sale of property	$ 80
Number of wireless towers \| item	95

Property, Plant, and Equipment, Number Of Sales Of Wireless Towers

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- Definition

Sale Leaseback Transaction, Deferred Gain, Amortization Period

+ References

No definition available.

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- Definition

The cash inflow from the sale of long-lived, physical assets that are used in the normal conduct of business to produce goods and services and not intended for resale.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 12
-Subparagraph (c)
-URI http://asc.fasb.org/extlink&oid=109223946&loc=d3e3179-108585

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

+ References

No definition available.

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- Definition

The portion of the deferred gain that was recognized in the current period.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 40
-Section 35
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=108788860&loc=d3e50609-112754

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- Definition

The amount of the gain recorded in connection with the transaction involving the sale of property to another party and the lease of the property back to the seller to be recognized in future periods.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 840
-SubTopic 40
-Section 25
-Paragraph 3
-URI http://asc.fasb.org/extlink&oid=77913853&loc=d3e49567-112750

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- Definition

The portion of the gain that will be recorded as income or a reduction in rent expense in future periods less amounts recognized in the current period.

+ References

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