Financial Instruments - Activity Related to the Company's Investment Portfolio and Available-for-sale Debt Securities Contractual Maturities (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
Jan. 24, 2020	Jan. 25, 2019	Jan. 24, 2020	Jan. 25, 2019	Apr. 26, 2019
Activities Related to Debt Securities Portfolio
Proceeds from sales	$ 2,531	$ 1,301	$ 5,789	$ 3,217
Gross realized gains	9	9	17	17
Gross realized losses	(2)	$ (36)	(13)	$ (55)
AFS Debt Maturities
Due in one year or less	3,595		3,595
Due after one year through five years	2,727		2,727
Due after five years through ten years	1,577		1,577
Due after ten years	53		53
Fair Value	$ 7,952		$ 7,952		$ 5,499

Fair value of investment in debt security measured at fair value with change in fair value recognized in other comprehensive income (available-for-sale), with single maturity date and allocated without single maturity date, maturing in sixth through tenth fiscal year following latest fiscal year. Excludes interim and annual periods when interim period is reported on rolling approach, from latest statement of financial position date.

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