Stockholders' Equity - Amounts Reclassified Out of Accumulated Other Comprehensive Income (Loss) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jan. 26, 2018	Jan. 27, 2017	Jan. 26, 2018	Jan. 27, 2017
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Operating expenses	$ 470	$ 668	$ 1,839	$ 2,059
Net revenues	1,523	1,404	4,270	4,038
Reclassification out of Accumulated Other Comprehensive Income
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Total reclassifications	(1)	(5)	(2)	(5)
Reclassification out of Accumulated Other Comprehensive Income | Recognized (Gains) Losses on Defined Benefit Obligations
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Operating expenses	(1)	0	(2)	1
Reclassification out of Accumulated Other Comprehensive Income | Realized Gains on Cash Flow Hedges
Reclassification Adjustment Out Of Accumulated Other Comprehensive Income [Line Items]
Net revenues	$ 0	$ (5)	$ 0	$ (6)