Property, Plant And Equipment (Narrative) (Details) - USD ($) $ in Millions	1 Months Ended	12 Months Ended
Jan. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Property, Plant and Equipment [Line Items]
Capital Leased Assets, Gross		$ 152	$ 171
Proceeds from sale of property		11	102
Property subject to leasebacks		9	97
Sale leasebacks, gains		$ 9	66
Sale leaseback, deferred gain amortization period		2 years
Sale leaseback, gain recognized		$ 36	23
Sale leaseback, gain remaining		$ 16	$ 43
Subsequent Event [Member] \| Towers [Member]
Property, Plant and Equipment [Line Items]
Proceeds from sale of property	$ 76
Aggregate carrying value of the towers	$ 1

Property, Plant, and Equipment, Carrying Value

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- Definition

Sale Leaseback Transaction, Deferred Gain, Amortization Period

+ References

No definition available.

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- Definition

Amount before accumulated depreciation of leased physical assets used in the normal conduct of business to produce goods and services.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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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.

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

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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.

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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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Amount of cash inflow before closing and debt issuance costs received by a seller-lessee in a sale-leaseback recognized in investing activities.

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