Fair Value Measurements (Details) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2015	Sep. 30, 2016
Fair Value - Other Financial Instruments
Carrying value of debt, net of unamortized discount	$ 8,300	$ 8,300
Midstream
Fair Value - Other Financial Instruments
Net Book Value	891
Total Pre-tax (Non-cash) Impairment Loss	841
Impaired proved oil and gas assets - international
Fair Value - Other Financial Instruments
Net Book Value	7,359
Total Pre-tax (Non-cash) Impairment Loss	4,693
Impaired proved oil and gas assets - domestic
Fair Value - Other Financial Instruments
Net Book Value	1,655
Total Pre-tax (Non-cash) Impairment Loss	1,030
Impaired Chemical property, plant, and equipment \| Chemical
Fair Value - Other Financial Instruments
Net Book Value	124
Total Pre-tax (Non-cash) Impairment Loss	121
Level 2
Fair Value - Other Financial Instruments
Debt estimated fair value		68
Level 3 \| Midstream
Fair Value - Other Financial Instruments
Assets, Fair value, nonrecurring	50
Level 3 \| Impaired proved oil and gas assets - international
Fair Value - Other Financial Instruments
Assets, Fair value, nonrecurring	2,666
Level 3 \| Impaired proved oil and gas assets - domestic
Fair Value - Other Financial Instruments
Assets, Fair value, nonrecurring	625
Level 3 \| Impaired Chemical property, plant, and equipment \| Chemical
Fair Value - Other Financial Instruments
Assets, Fair value, nonrecurring	3
Total Fair Value
Fair Value - Other Financial Instruments
Debt estimated fair value	8,400	9,100
Recurring
Assets:
Netting and Collateral	(535)	(149)
Liabilities:
Netting and Collateral	(525)	(171)
Recurring \| Level 1
Assets:
Commodity derivatives	557	129
Available for sale investment	167
Liabilities:
Commodity derivatives	544	150
Recurring \| Level 2
Assets:
Commodity derivatives	87	55
Liabilities:
Commodity derivatives	404	310
Recurring \| Total Fair Value
Assets:
Commodity derivatives	109	35
Available for sale investment	167
Liabilities:
Commodity derivatives	$ 423	$ 289
Non recurring \| Low end of range
Fair Value - Other Financial Instruments
Risk adjusted discount rate	8.00%
Non recurring \| High end of range
Fair Value - Other Financial Instruments
Risk adjusted discount rate	20.00%

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Net book value of impaired assets

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Value of investment recorded as available for sale asset.

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This element represents the aggregate of the assets reported on the balance sheet at period end measured at fair value on a nonrecurring basis by the entity. This element is intended to be used in connection with the fair value disclosures required in the footnote disclosures to the financial statements.

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Fair value portion of debt instrument payable, including, but not limited to, notes payable and loans payable.

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Fair value of liability associated with financial asset or other contract with one or more underlyings, notional amount or payment provision or both, and the contract can be net settled by means outside the contract or delivery of an asset, and obligation to return cash collateral under master netting arrangements.

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Interest rate used to find the present value of an amount to be paid or received in the future as an input to measure fair value. For example, but not limited to, weighted average cost of capital (WACC), cost of capital, cost of equity and cost of debt.

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The expense recorded to reduce the value of oil and gas assets consisting of proved properties and unproved properties as the estimate of future successful production from these properties is reduced.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Fair value as of the balance sheet date of price risk derivative assets, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as assets on the balance sheet.

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Fair value as of the balance sheet date of price risk derivative liabilities, which includes all such derivative instruments in hedging and nonhedging relationships that are recognized as liabilities on the balance sheet.

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