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Financial Instruments - Information on Available-for-sale Investments (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2020	Mar. 31, 2019	Dec. 31, 2019
Debt Securities, Available-for-sale [Line Items]
Debt securities, amortized cost	$ 64		$ 1,768
Debt securities, unrealized gains	0		17
Debt securities, unrealized losses	0		0
Debt securities, fair value	64		1,785
Publicly traded equity securities, fair value	779		838
Total debt and publicly traded equity securities, fair value	843		2,623
Unrealized net losses (gains)	4	$ (114)
U.S. government and agency securities
Debt Securities, Available-for-sale [Line Items]
Debt securities, amortized cost	62		266
Debt securities, unrealized gains	0		3
Debt securities, unrealized losses	0		0
Debt securities, fair value	62		269
Foreign government bonds
Debt Securities, Available-for-sale [Line Items]
Debt securities, amortized cost	2		0
Debt securities, unrealized gains	0		0
Debt securities, unrealized losses	0		0
Debt securities, fair value	2		0
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Debt securities, amortized cost	0		668
Debt securities, unrealized gains	0		0
Debt securities, unrealized losses	0		0
Debt securities, fair value	0		668
Corporate notes and bonds
Debt Securities, Available-for-sale [Line Items]
Debt securities, amortized cost	0		608
Debt securities, unrealized gains	0		13
Debt securities, unrealized losses	0		0
Debt securities, fair value	0		621
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Debt securities, amortized cost	0		226
Debt securities, unrealized gains	0		1
Debt securities, unrealized losses	0		0
Debt securities, fair value	$ 0		$ 227

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Debt Securities and Equity Securities, FV-NI

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