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Financial Instruments - Information on Debt and Equity Securities (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2019	Dec. 31, 2018
Debt Securities, Available-for-sale [Line Items]
Debt securities, amortized cost	$ 1,768	$ 7,340
Debt securities, gross unrealized gains	17	6
Debt securities, gross unrealized losses	0	(85)
Debt securities, fair value	1,785	7,261
Publicly traded equity securities, fair value	838	456
Total debt and publicly traded equity securities, fair value	2,623	7,717
Unrealized net gains	160	(35)
Commercial paper
Debt Securities, Available-for-sale [Line Items]
Debt securities, amortized cost	668	0
Debt securities, gross unrealized gains	0	0
Debt securities, gross unrealized losses	0	0
Debt securities, fair value	668	0
Corporate notes and bonds
Debt Securities, Available-for-sale [Line Items]
Debt securities, amortized cost	608	4,985
Debt securities, gross unrealized gains	13	3
Debt securities, gross unrealized losses	0	(68)
Debt securities, fair value	621	4,920
U.S. government and agency securities
Debt Securities, Available-for-sale [Line Items]
Debt securities, amortized cost	266	895
Debt securities, gross unrealized gains	3	2
Debt securities, gross unrealized losses	0	(5)
Debt securities, fair value	269	892
Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Debt securities, amortized cost	226	1,285
Debt securities, gross unrealized gains	1	1
Debt securities, gross unrealized losses	0	(11)
Debt securities, fair value	227	1,275
Foreign government bonds
Debt Securities, Available-for-sale [Line Items]
Debt securities, amortized cost	0	167
Debt securities, gross unrealized gains	0	0
Debt securities, gross unrealized losses	0	(1)
Debt securities, fair value	0	166
Mortgage-backed securities
Debt Securities, Available-for-sale [Line Items]
Debt securities, amortized cost	0	8
Debt securities, gross unrealized gains	0	0
Debt securities, gross unrealized losses	0	0
Debt securities, fair value	0	8
Fair Value, Measurements, Recurring | Corporate notes and bonds
Debt Securities, Available-for-sale [Line Items]
Debt securities, fair value	621	4,835
Fair Value, Measurements, Recurring | U.S. government and agency securities
Debt Securities, Available-for-sale [Line Items]
Debt securities, fair value	209	731
Fair Value, Measurements, Recurring | Asset-backed securities
Debt Securities, Available-for-sale [Line Items]
Debt securities, fair value	227	1,253
Fair Value, Measurements, Recurring | Foreign government bonds
Debt Securities, Available-for-sale [Line Items]
Debt securities, fair value	0	166
Fair Value, Measurements, Recurring | Publicly traded equity securities
Debt Securities, Available-for-sale [Line Items]
Publicly traded equity securities, fair value	$ 518	$ 147

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Debt Securities and Equity Securities, FV-NI

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