Financial Instruments Narrative (Details) bbl in Millions, $ in Millions	12 Months Ended
Dec. 31, 2018 USD ($) bbl	Dec. 31, 2017 USD ($) bbl
Derivatives, Fair Value [Line Items]
Debt designated as net investment in foreign operations		$ 884
Loss recognized in AOCI	$ 29	85
Investment Segment
Derivatives, Fair Value [Line Items]
Fair value of derivative instruments with credit risk related contingent features in a liability position	$ 0	$ 17
Commodity contracts \| Energy Segment \| Not designated as hedging instrument
Derivatives, Fair Value [Line Items]
Derivative volume (barrels) \| bbl		15
Commodity contracts not considered probable of settlement \| Energy Segment \| Not designated as hedging instrument
Derivatives, Fair Value [Line Items]
Derivative volume (barrels) \| bbl	2	6

Fair value of credit risk derivative liability.

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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Nominal volume used to calculate payments on a derivative instrument.

+ References

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Fair value of all derivative liabilities designated as hedges of net investment in foreign operations.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4B
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Amount, after tax, of reclassification from accumulated other comprehensive income (AOCI) of gain (loss) from increase (decrease) in fair value of net investment hedge.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 815
-SubTopic 10
-Section 50
-Paragraph 4CCC
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
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