The accounting guidance for fair value measurements provides a framework for measuring fair value on either a recurring or nonrecurring basis, whereby the inputs used in valuation techniques are assigned a hierarchical level. The following are the three levels of inputs to measure fair value:

Level 1: Observable inputs that reflect quoted prices (unadjusted) for identical assets or liabilities in active markets.

Level 2: Inputs that reflect quoted prices for identical assets or liabilities in less active markets; quoted prices for similar assets or liabilities in active markets; benchmark yields, reported trades, broker/dealer quotes, inputs other than quoted prices that are observable for the assets or liabilities; or inputs that are derived principally from or corroborated by observable market data by correlation or other means.

Level 3: Unobservable inputs that reflect our own assumptions incorporated in valuation techniques used to measure fair value. These assumptions are required to be consistent with market participant assumptions that are reasonably available.

We consider an active market to be one in which transactions for the asset or liability occur with sufficient frequency and volume to provide pricing information on an ongoing basis, and consider an inactive market to be one in which there are infrequent or few transactions for the asset or liability, the prices are not current, or price quotations vary substantially either over time or among market makers. Where appropriate, our own or the counterparty’s non-performance risk is considered in measuring the fair values of liabilities and assets, respectively.

The following is a summary of our investments at their cost or amortized cost for the years ended April 30, 2021 and April 24, 2020 (in millions):

	April 30, 2021		April 24, 2020
Corporate bonds	$	58	$	155
U.S. Treasury and government debt securities		8		68
Certificates of deposit		61		158
Mutual funds		40		33
Total debt and equity securities	$	167	$	414

The fair value of our investments approximates their cost or amortized cost for both periods presented.

During fiscal 2020, we sold approximately $1.0 billion of corporate bonds held by foreign subsidiaries and recognized a gain on sale of $14 million, which is presented in other (expense) income, net on our consolidated statement of income.

The following table presents the contractual maturities of our debt investments as of April 30, 2021 (in millions):

	Amortized Cost		Fair Value
Due in one year or less	$	102	$	102
Due after one year through five years		20		21
Due after five years through ten years		5		5
	$	127	$	128

Actual maturities may differ from the contractual maturities because borrowers may have the right to call or prepay certain obligations.

The following table summarizes our financial assets and liabilities measured at fair value on a recurring basis (in millions):

	April 30, 2021
				Fair Value Measurements at Reporting Date Using
	Total			Level 1		Level 2
Cash	$	4,468		$	4,468	$	—
Corporate bonds		59			—		59
U.S. Treasury and government debt securities		8			4		4
Certificates of deposit		61			—		61
Total cash, cash equivalents and short-term investments	$	4,596		$	4,472	$	124
Other items:
Mutual funds ⁽¹⁾	$	8		$	8	$	—
Mutual funds ⁽²⁾	$	32		$	32	$	—
Foreign currency exchange contracts assets ⁽¹⁾	$	9		$	—	$	9
Foreign currency exchange contracts liabilities ⁽³⁾	$	(1	)	$	—	$	(1	)

	April 24, 2020
				Fair Value Measurements at Reporting Date Using
	Total			Level 1		Level 2
Cash	$	2,500		$	2,500	$	—
Corporate bonds		156			—		156
U.S. Treasury and government debt securities		68			44		24
Certificates of deposit		158			—		158
Total cash, cash equivalents and short-term investments	$	2,882		$	2,544	$	338
Other items:
Mutual funds ⁽¹⁾	$	6		$	6	$	—
Mutual funds ⁽²⁾	$	27		$	27	$	—
Foreign currency exchange contracts assets ⁽¹⁾	$	4		$	—	$	4
Foreign currency exchange contracts liabilities ⁽³⁾	$	(2	)	$	—	$	(2	)

Our Level 2 debt instruments are held by a custodian who prices some of the investments using standard inputs in various asset price models or obtains investment prices from third-party pricing providers that incorporate standard inputs in various asset price models. These pricing providers utilize the most recent observable market information in pricing these securities or, if specific prices are not available for these securities, use other observable inputs like market transactions involving identical or comparable securities. We review Level 2 inputs and fair value for reasonableness and the values may be further validated by comparison to multiple independent pricing sources. In addition, we review third-party pricing provider models, key inputs and assumptions and understand the pricing processes at our third-party providers in determining the overall reasonableness of the fair value of our Level 2 debt instruments. As of April 30, 2021 and April 24, 2020, we have not made any adjustments to the prices obtained from our third-party pricing providers.

As of April 30, 2021 and April 24, 2020, the fair value of our long-term debt was approximately $2,736 million and $1,176 million, respectively. The fair value of our long-term debt was based on observable market prices in a less active market. The fair value of our commercial paper notes approximated their carrying value. All of our debt obligations are categorized as Level 2 instruments.