Derivative and Financial Instruments - Cost Basis to Fair Value (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Sep. 30, 2020	Sep. 30, 2020	Dec. 31, 2019
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis	$ 480	$ 480	$ 241
Fair Value	482	482	241
Proceeds from sales and redemptions of investments in debt securities classified as available for sale	109	298
Corporate Bonds [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis	283	283	159
Fair Value	285	285	159
Commercial Paper [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis	111	111	38
Fair Value	111	111	38
Government obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis	21	21	25
Fair Value	21	21	25
U.S. Government Agency Obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis	17	17	0
Fair Value	17	17	0
Foreign government obligations [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis	2	2	0
Fair Value	2	2	0
Asset-backed Securities [Member]
Schedule Of Available For Sale Securities [Line Items]
Amortized Cost Basis	46	46	19
Fair Value	$ 46	$ 46	$ 19

Amortized cost of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 320
-SubTopic 10
-Section 50
-Paragraph 2
-Subparagraph (a)
-URI http://asc.fasb.org/extlink&oid=121645371&loc=d3e27161-111563

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 326
-SubTopic 30
-Section 45
-Paragraph 1
-URI http://asc.fasb.org/extlink&oid=121558606&loc=SL82898722-210454

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- Definition

Fair value portion of investment securities, including, but not limited to, marketable securities, derivative financial instruments, and investments accounted for under the equity method.

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
-SubTopic 10
-Section 50
-Paragraph 2
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Amount of cash inflow from sale, maturity, prepayment and call of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale).

+ References

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 230
-SubTopic 10
-Section 45
-Paragraph 11
-URI http://asc.fasb.org/extlink&oid=121586364&loc=d3e3151-108585

Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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-Name Accounting Standards Codification
-Topic 230
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-Section 45
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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.

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No definition available.

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