Available-for-Sale Debt Securities (Tables)

6 Months Ended

Jun. 30, 2020

Debt Securities, Available-for-sale [Abstract]

Reconciliation of Available-for-Sale Debt Securities from Cost Basis to Fair Value

The following table summarizes our available-for-sale debt securities (in millions):

	June 30, 2020								December 31, 2019
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value		Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
U.S. treasury securities	$	2,479	$	19	$	—	$	2,498	$	2,433	$	—	$	—	$	2,433
Certificates of deposit	2,783		—		—		2,783		3,517		—		—		3,517
U.S. government agencies securities	101		—		—		101		1,081		—		—		1,081
Non-U.S. government securities	145		—		—		145		174		—		—		174
Corporate debt securities	8,755		31		(2)		8,784		9,203		2		(1)		9,204
Residential mortgage and asset-backed securities	621		3		—		624		91		—		—		91
Total	$	14,884	$	53	$	(2)	$	14,935	$	16,499	$	2	$	(1)	$	16,500

Summary of Classification of Available-for-Sale Debt Securities

The following table summarizes the classification of our available-for-sale debt securities in our Condensed Consolidated Balance Sheets (in millions):

	June 30, 2020		December 31, 2019
Cash and cash equivalents	$	491	$	2,291
Short-term marketable securities	12,168		12,721
Long-term marketable securities	2,276		1,488
Total	$	14,935	$	16,500

Summary of Available-for-Sale Debt Securities by Contractual Maturity

The following table summarizes our available-for-sale debt securities by contractual maturity (in millions):

	June 30, 2020
	Amortized Cost		Fair Value
Within one year	$	12,623	$	12,659
After one year through five years	2,197		2,212
After five years	64		64
Total	$	14,884	$	14,935

Summary of Available-for-Sale Debt Securities in a Continuous Loss Position

The following table summarizes our available-for-sale debt securities in an unrealized loss position (in millions):

	Less Than 12 Months				12 Months or Greater				Total
	Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value		Gross Unrealized Losses		Estimated Fair Value
June 30, 2020
Corporate debt securities	$	(2)	$	1,175	$	—	$	—	$	(2)	$	1,175
December 31, 2019
Corporate debt securities	$	(1)	$	1,866	$	—	$	4	$	(1)	$	1,870