Investments

3 Months Ended

Mar. 31, 2021

Debt Securities, Available-for-sale [Abstract]

Marketable Debt Securities

The following is a summary of our available-for-sale debt securities recorded within short-term and long-term investments on the condensed consolidated balance sheets (in millions):


	March 31, 2021
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Available-for-sale securities:
Commercial paper	$	458	$	—	$	—	$	458
Corporate notes and bonds	2,319		6		(1)		2,324
Certificates of deposit	74		—		—		74
U.S. government and agency securities	97		—		—		97
Mortgage and asset backed securities	31		—		(1)		30

Total available-for-sale securities	$	2,979	$	6	$	(2)	$	2,983


	December 31, 2020
	Amortized Cost		Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Available-for-sale securities:
Commercial paper	$	406	$	—	$	—	$	406
Corporate notes and bonds	2,298		10		—		2,308
Certificates of deposit	23		—		—		23
U.S. government and agency securities	145		1		—		146
Total available-for-sale securities	$	2,872	$	11	$	—	$	2,883

As of March 31, 2021, the contractual maturities of our available-for-sale debt securities, excluding those securities classified within cash and cash equivalents on the condensed consolidated balance sheet and mortgage and asset backed securities that do not have a single maturity, did not exceed 36 months. The fair values of available-for-sale securities, by remaining contractual maturity, are as follows (in millions):


	March 31, 2021
Due within 1 year	$	1,635
Due in 1 year through 5 years	1,318
Instruments not due in single maturity	30
Total	$	2,983

As of March 31, 2021, the fair values and the gross unrealized losses of these available-for-sale debt securities, classified by the length of time that the securities have been in a continuous unrealized loss position, and aggregated by investment types, excluding those securities classified within cash and cash equivalents on the condensed consolidated balance sheets (in millions), are as follows:


	March 31, 2021
	Less than 12 Months				12 Months or Greater				Total
	Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses		Fair Value		Gross Unrealized Losses

Corporate notes and bonds	$	1,027	$	(1)	$	—	$	—	$	1,027	$	(1)


Mortgage and asset backed securities	27		(1)		—		—		27		(1)
Total	$	1,054	$	(2)	$	—	$	—	$	1,054	$	(2)

As of December 31, 2020, the gross unrealized losses related to fair value $637 million available-for-sale debt securities that have been in a continuous unrealized loss position were not material.

The decline in fair value below amortized cost basis was not considered other than temporary as it is more likely than not we will hold the securities until maturity or a recovery of the cost basis, and credit-related impairment losses were not deemed material as of March 31, 2021.

Strategic Investments

As of March 31, 2021 and December 31, 2020, the total amount of equity investments in privately-held companies included in other assets on our condensed consolidated balance sheets was $37 million and $28 million, respectively. We classify these assets as Level 3 within the fair value hierarchy as only an impairment or observable adjustment is recognized based on observable transaction price at the transaction date of identical or similar investment of the same issuer and other unobservable inputs such as volatility.