
	December 31, 2025
	Amortized Cost			Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Available-for-sale debt securities:
Commercial paper		$	173	$	—	$	—	$	173
Corporate notes and bonds		4,759		34		—		4,793
Certificates of deposit		11		—		—		11
U.S. government and agency securities		1,257		6		—		1,263
Mortgage-backed and asset-backed securities		103		—		(14)		89
Total available-for-sale debt securities		$	6,303	$	40	$	(14)	$	6,329


	December 31, 2024
	Amortized Cost			Gross Unrealized Gains		Gross Unrealized Losses		Estimated Fair Value
Available-for-sale debt securities:
Commercial paper		$	336	$	—	$	—	$	336
Corporate notes and bonds		4,966		15		(5)		4,976
Certificates of deposit		67		—		—		67
U.S. government and agency securities		2,103		3		(2)		2,104
Mortgage-backed and asset-backed securities		104		—		(18)		86
Total available-for-sale debt securities		$	7,576	$	18	$	(25)	$	7,569

As of December 31, 2025, the contractual maturities of our available-for-sale debt securities, excluding those securities classified within cash and cash equivalents on the consolidated balance sheet and mortgage-backed and asset-backed securities that do not have a single maturity, did not exceed 37 months. The fair values of available-for-sale debt securities, by remaining contractual maturity, are as follows (in millions):

As of December 31, 2025 and 2024, unrealized losses of $14 million and $18 million, respectively, are from available-for-sale debt securities in a continuous unrealized loss position greater than 12 months. As of December 31, 2025, the fair value of available-for-sale debt securities in a continuous unrealized loss position totaled $171 million, the majority of which was in a continuous unrealized loss position for greater than 12 months. As of December 31, 2024, the fair value of available-for-sale debt securities in a continuous unrealized loss position totaled $2,419 million, the majority of which was in a continuous unrealized loss position for less than 12 months.

For all available-for-sale debt securities that were in unrealized loss positions, we have determined that it is more likely than not we will hold the securities until maturity or a recovery of the cost basis. Unrealized losses on available-for-sale debt securities were due primarily to changes in market interest rates, and credit-related impairment losses were immaterial as of December 31, 2025.

As of December 31, 2025 and 2024, the total amount of strategic investments in privately held companies included in our consolidated balance sheets was $1,542 million and $472 million, respectively. Our strategic investments are predominantly comprised of non-marketable equity investments, which are primarily accounted for using the measurement alternative. Under this approach, the investments are measured at cost minus impairment, if any, plus or minus changes resulting from qualifying observable price changes resulting from the issuance of similar or identical securities in an orderly transaction by the same issuer. Determining whether an observed transaction is similar to a security within our portfolio requires judgment based on the rights and preferences of the securities. Recording upward and downward adjustments to the carrying value of our non-marketable equity investments as a result of observable price changes requires quantitative assessments of the fair value of our non-marketable equity investments using various valuation methodologies and involves the use of estimates. The adjustments made during the years ended December 31, 2025, 2024 and 2023 were immaterial. The remaining strategic investments are accounted for using the equity method of accounting as we have the ability to exercise significant influence but not control over the investee. For the years ended December 31, 2025, 2024 and 2023, our share of the investees’ results of operations included in other expense, net in our consolidated statements of comprehensive income was immaterial. We classify these fair value measurements as Level 3 within the fair value hierarchy.