SUPPLEMENTAL FINANCIAL STATEMENT INFORMATION Narrative (Details) - USD ($) $ in Millions	3 Months Ended	6 Months Ended	12 Months Ended
Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2019	Jun. 30, 2018	Dec. 31, 2018
Temporary investments	$ 477		$ 477		$ 402
Allowance for doubtful accounts	85		85		81
Accumulated depreciation	20,600		20,600		20,500
Depreciation expense	300	$ 309	597	$ 615
Capital Expenditures Incurred but Not yet Paid			101		135
Interest payments			375	$ 378
Asset retirement obligation	$ 95		$ 95		$ 86

Amount of accumulated depreciation, depletion and amortization for physical assets used in the normal conduct of business to produce goods and services.

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A valuation allowance for trade and other receivables due to an Entity within one year (or the normal operating cycle, whichever is longer) that are expected to be uncollectible.

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The carrying amount of a liability for an asset retirement obligation. An asset retirement obligation is a legal obligation associated with the disposal or retirement of a tangible long-lived asset that results from the acquisition, construction or development, or the normal operations of a long-lived asset, except for certain obligations of lessees.

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Future cash outflow to pay for purchases of fixed assets that have occurred.

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The amount of expense recognized in the current period that reflects the allocation of the cost of tangible assets over the assets' useful lives. Includes production and non-production related depreciation.

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Amount of cash paid for interest, including, but not limited to, capitalized interest and payment to settle zero-coupon bond attributable to accreted interest of debt discount and debt instrument with insignificant coupon interest rate in relation to effective interest rate of borrowing attributable to accreted interest of debt discount; classified as operating and investing activities.

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Amount of short-term, highly liquid investments that are both readily convertible to known amounts of cash and so near their maturity that they present insignificant risk of changes in value because of changes in interest rates, classified as other. Excludes cash and cash equivalents within disposal group and discontinued operation.

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