Financial Instruments - Investments by Category and Related Balance Sheet Presentation (Details) - USD ($) $ in Millions	Apr. 24, 2020	Apr. 26, 2019
Schedule of Investments [Line Items]
Cost	$ 6,847	$ 5,540
Unrealized Gains	135	20
Unrealized Losses	(141)	(61)
Fair Value	6,841	5,499
Investments
Schedule of Investments [Line Items]
Fair Value	6,808	5,455
Other Assets
Schedule of Investments [Line Items]
Fair Value	33	44
Level 1 | U.S. government and agency securities
Schedule of Investments [Line Items]
Cost	542	529
Unrealized Gains	47	1
Unrealized Losses	0	(7)
Fair Value	589	523
Level 1 | U.S. government and agency securities | Investments
Schedule of Investments [Line Items]
Fair Value	589	523
Level 1 | U.S. government and agency securities | Other Assets
Schedule of Investments [Line Items]
Fair Value	0	0
Level 2
Schedule of Investments [Line Items]
Cost	6,269	4,964
Unrealized Gains	88	19
Unrealized Losses	(138)	(51)
Fair Value	6,219	4,932
Level 2 | Investments
Schedule of Investments [Line Items]
Fair Value	6,219	4,932
Level 2 | Other Assets
Schedule of Investments [Line Items]
Fair Value	0	0
Level 2 | U.S. government and agency securities
Schedule of Investments [Line Items]
Cost	746	387
Unrealized Gains	1	1
Unrealized Losses	0	(7)
Fair Value	747	381
Level 2 | U.S. government and agency securities | Investments
Schedule of Investments [Line Items]
Fair Value	747	381
Level 2 | U.S. government and agency securities | Other Assets
Schedule of Investments [Line Items]
Fair Value	0	0
Level 2 | Corporate debt securities
Schedule of Investments [Line Items]
Cost	4,285	3,500
Unrealized Gains	66	14
Unrealized Losses	(90)	(21)
Fair Value	4,261	3,493
Level 2 | Corporate debt securities | Investments
Schedule of Investments [Line Items]
Fair Value	4,261	3,493
Level 2 | Corporate debt securities | Other Assets
Schedule of Investments [Line Items]
Fair Value	0	0
Level 2 | Mortgage-backed securities
Schedule of Investments [Line Items]
Cost	705	537
Unrealized Gains	20	3
Unrealized Losses	(28)	(20)
Fair Value	697	520
Level 2 | Mortgage-backed securities | Investments
Schedule of Investments [Line Items]
Fair Value	697	520
Level 2 | Mortgage-backed securities | Other Assets
Schedule of Investments [Line Items]
Fair Value	0	0
Level 2 | Non-U.S. government and agency securities
Schedule of Investments [Line Items]
Cost	34	11
Unrealized Gains	0	0
Unrealized Losses	0	0
Fair Value	34	11
Level 2 | Non-U.S. government and agency securities | Investments
Schedule of Investments [Line Items]
Fair Value	34	11
Level 2 | Non-U.S. government and agency securities | Other Assets
Schedule of Investments [Line Items]
Fair Value	0	0
Level 2 | Other asset-backed securities
Schedule of Investments [Line Items]
Cost	499	529
Unrealized Gains	1	1
Unrealized Losses	(20)	(3)
Fair Value	480	527
Level 2 | Other asset-backed securities | Investments
Schedule of Investments [Line Items]
Fair Value	480	527
Level 2 | Other asset-backed securities | Other Assets
Schedule of Investments [Line Items]
Fair Value	0	0
Level 3 | Auction rate securities
Schedule of Investments [Line Items]
Cost	36	47
Unrealized Gains	0	0
Unrealized Losses	(3)	(3)
Fair Value	33	44
Level 3 | Auction rate securities | Investments
Schedule of Investments [Line Items]
Fair Value	0	0
Level 3 | Auction rate securities | Other Assets
Schedule of Investments [Line Items]
Fair Value	$ 33	$ 44