Fair value of investment other than investment in equity security, investment in debt security and equity method investment. Includes, but is not limited to, investment in certain entities that calculate net asset value per share. Example includes, but is not limited to, investment in hedge fund, venture capital fund, private equity fund, and real estate partnership or fund.

Reference 1: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 820
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-Section 50
-Paragraph 6A
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
-Publisher FASB
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- Definition

This element represents the aggregate cost of investments accounted for under the equity method of accounting.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
-Name Accounting Standards Codification
-Topic 210
-SubTopic 10
-Section S99
-Paragraph 1
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- Definition

Difference between amount at which an investment accounted for under the equity method of accounting is carried (reported) on the balance sheet and amount of underlying equity in net assets the reporting Entity has in the investee.

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-Publisher FASB
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-SubTopic 10
-Section 50
-Paragraph 3
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- Definition

The percentage of ownership of common stock or equity participation in the investee accounted for under the equity method of accounting.

+ References

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-Publisher FASB
-Name Accounting Standards Codification
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-SubTopic 10
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- Definition

This item represents the aggregate value of each identified investment accounted for under the equity method of accounting based on the quoted market price for those investments in common stock for which a quoted market price is available.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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- Definition

This item represents the carrying amount on the entity's balance sheet of its investment in common stock of an equity method investee. This is not an indicator of the fair value of the investment, rather it is the initial cost adjusted for the entity's share of earnings and losses of the investee, adjusted for any distributions (dividends) and other than temporary impairment (OTTI) losses recognized.

+ References

Reference 1: http://fasb.org/us-gaap/role/ref/legacyRef
-Publisher FASB
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-Topic 323
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-Publisher FASB
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-Section S99
-Paragraph 1
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Fair value portion of investments accounted under the equity method.

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-Publisher FASB
-Name Accounting Standards Codification
-Topic 323
-SubTopic 10
-Section 25
-Paragraph 2
-URI http://asc.fasb.org/extlink&oid=117311354&loc=d3e32014-111567

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- Definition

Useful life of finite-lived intangible assets, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.

+ References

No definition available.

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- Definition

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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Investments Investments (Limited Partnership Investments) (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Jan. 02, 2020	Dec. 31, 2019
Limited Partnership [Member] \| Fair Value Measured at Net Asset Value Per Share [Member]
Net Investment Income [Line Items]
Investments	$ 331		$ 320
BeiGene [Member]
Net Investment Income [Line Items]
Carrying value of equity method investment	$ 2,600
Equity Method Investment, Aggregate Cost		$ 2,800
Ownership percentage	20.50%	20.50%
Equity Method Investments,Quoted Market Price		$ 2,600
Equity Method Investment, Difference Between Carrying Amount and Underlying Equity		$ 2,400
Equity Method Investments, Fair Value Disclosure	$ 2,000
Minimum [Member] \| BeiGene [Member]
Net Investment Income [Line Items]
Finite-Lived Intangible Asset, Useful Life	8 years
Maximum [Member] \| BeiGene [Member]
Net Investment Income [Line Items]
Finite-Lived Intangible Asset, Useful Life	15 years