Stockholders' Equity - Accumulated Other Comprehensive Income (Loss) by Component Net of Tax (Detail) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Oct. 25, 2019	Oct. 26, 2018	Oct. 25, 2019	Oct. 26, 2018
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balances	$ 863	$ 1,922	$ 1,090	$ 2,276
Other comprehensive income (loss), net of tax			21
Amounts reclassified from AOCI, net of tax			(14)
Other comprehensive income (loss)	3	(5)	7	(5)
Balances	536	1,530	536	1,530
Foreign Currency Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balances			(34)
Other comprehensive income (loss), net of tax			(2)
Amounts reclassified from AOCI, net of tax			0
Other comprehensive income (loss)			(2)
Balances	(36)		(36)
Defined Benefit Obligation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balances			(3)
Other comprehensive income (loss), net of tax			0
Amounts reclassified from AOCI, net of tax			0
Other comprehensive income (loss)			0
Balances	(3)		(3)
Unrealized Gains (Losses) on Available-for-Sale Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balances			(7)
Other comprehensive income (loss), net of tax			22
Amounts reclassified from AOCI, net of tax			(14)
Other comprehensive income (loss)			8
Balances	1		1
Unrealized Gains (Losses) on Derivative Instruments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balances			1
Other comprehensive income (loss), net of tax			1
Amounts reclassified from AOCI, net of tax			0
Other comprehensive income (loss)			1
Balances	2		2
AOCI Attributable to Parent
Accumulated Other Comprehensive Income (Loss) [Line Items]
Balances	(39)	(70)	(43)	(70)
Other comprehensive income (loss)	3	(5)	7	(5)
Balances	$ (36)	$ (75)	$ (36)	$ (75)