Accumulated Other Comprehensive Loss - Changes in AOCI (Details) - USD ($)		3 Months Ended						9 Months Ended
		Jan. 24, 2020	Oct. 25, 2019	Jul. 26, 2019	Jan. 25, 2019	Oct. 26, 2018	Jul. 27, 2018	Jan. 24, 2020	Jan. 25, 2019	Apr. 27, 2019	[1]	Apr. 28, 2018
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance		$ 50,719,000,000	$ 50,497,000,000	$ 50,212,000,000	$ 49,714,000,000	$ 50,329,000,000	$ 50,822,000,000	$ 50,212,000,000	$ 50,822,000,000
Other comprehensive income (loss)		65,000,000	(127,000,000)	227,000,000	154,000,000	(292,000,000)	(584,000,000)	165,000,000	(722,000,000)
Cumulative effect of change in accounting principle										$ (33,000,000)		$ 0	[2]
Ending balance		51,953,000,000	50,719,000,000	50,497,000,000	49,941,000,000	49,714,000,000	50,329,000,000	51,953,000,000	49,941,000,000
Unrealized (Loss) Gain on Investment Securities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance				(45,000,000)			(194,000,000)	(45,000,000)	(194,000,000)
Other comprehensive income (loss) before reclassifications								94,000,000	(7,000,000)
Reclassifications								(1,000,000)	30,000,000
Other comprehensive income (loss)								93,000,000	23,000,000
Cumulative effect of change in accounting principle												47,000,000
Ending balance		48,000,000			(124,000,000)			48,000,000	(124,000,000)
Other Comprehensive Income (Loss), Tax [Abstract]
Other comprehensive income (loss) before reclassifications, tax expense (benefit)								7,000,000	(2,000,000)
Reclassifications, tax expense (benefit)								1,000,000	(2,000,000)
Cumulative Translation Adjustments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance				(1,383,000,000)			(11,000,000)	(1,383,000,000)	(11,000,000)
Other comprehensive income (loss) before reclassifications								(116,000,000)	(1,124,000,000)
Reclassifications								0	0
Other comprehensive income (loss)								(116,000,000)	(1,124,000,000)
Cumulative effect of change in accounting principle												0
Ending balance		(1,499,000,000)			(1,135,000,000)			(1,499,000,000)	(1,135,000,000)
Other Comprehensive Income (Loss), Tax [Abstract]
Other comprehensive income (loss) before reclassifications, tax expense (benefit)								0	(8,000,000)
Net Investment Hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance				(169,000,000)				(169,000,000)
Other comprehensive income (loss) before reclassifications								187,000,000	0
Reclassifications								0	0
Other comprehensive income (loss)								187,000,000
Ending balance		18,000,000						18,000,000
Other Comprehensive Income (Loss), Tax [Abstract]
Other comprehensive income (loss) before reclassifications, tax expense (benefit)								0
Net Investment Hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance							(257,000,000)		(257,000,000)
Other comprehensive income (loss)									0
Cumulative effect of change in accounting principle												0
Ending balance					(257,000,000)				(257,000,000)
Other Comprehensive Income (Loss), Tax [Abstract]
Other comprehensive income (loss) before reclassifications, tax expense (benefit)									0
Net Change in Retirement Obligations
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance				(1,308,000,000)			(1,117,000,000)	(1,308,000,000)	(1,117,000,000)
Other comprehensive income (loss) before reclassifications								(1,000,000)	0
Reclassifications								39,000,000	65,000,000
Other comprehensive income (loss)								38,000,000	65,000,000
Cumulative effect of change in accounting principle												0
Ending balance		(1,270,000,000)			(1,052,000,000)			(1,270,000,000)	(1,052,000,000)
Other Comprehensive Income (Loss), Tax [Abstract]
Other comprehensive income (loss) before reclassifications, tax expense (benefit)								0	0
Reclassifications, tax expense (benefit)								(9,000,000)	(15,000,000)
Unrealized Gain (Loss) on Cash Flow Hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance				194,000,000				194,000,000
Other comprehensive income (loss) before reclassifications								106,000,000
Reclassifications								(143,000,000)
Other comprehensive income (loss)								(37,000,000)
Ending balance		157,000,000						157,000,000
Other Comprehensive Income (Loss), Tax [Abstract]
Other comprehensive income (loss) before reclassifications, tax expense (benefit)								38,000,000
Reclassifications, tax expense (benefit)								47,000,000
Unrealized (Loss) Gain on Cash Flow Hedges
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance							(207,000,000)		(207,000,000)
Other comprehensive income (loss) before reclassifications									353,000,000
Reclassifications									(36,000,000)
Other comprehensive income (loss)									317,000,000
Cumulative effect of change in accounting principle												0
Ending balance					110,000,000				110,000,000
Other Comprehensive Income (Loss), Tax [Abstract]
Other comprehensive income (loss) before reclassifications, tax expense (benefit)									116,000,000
Reclassifications, tax expense (benefit)									16,000,000
Total Accumulated Other Comprehensive (Loss) Income
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance		(2,611,000,000)	(2,484,000,000)	(2,711,000,000)	(2,612,000,000)	(2,323,000,000)	(1,786,000,000)	(2,711,000,000)	(1,786,000,000)
Other comprehensive income (loss) before reclassifications								270,000,000	(778,000,000)
Reclassifications								(105,000,000)	59,000,000
Other comprehensive income (loss)		65,000,000	(127,000,000)	227,000,000	154,000,000	(289,000,000)	(584,000,000)	165,000,000	(719,000,000)
Cumulative effect of change in accounting principle	[2]											47,000,000
Ending balance		(2,546,000,000)	(2,611,000,000)	(2,484,000,000)	(2,458,000,000)	(2,612,000,000)	(2,323,000,000)	(2,546,000,000)	(2,458,000,000)
Retained Earnings
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Beginning balance		27,018,000,000	26,377,000,000	26,270,000,000	25,171,000,000	24,730,000,000	24,379,000,000	26,270,000,000	24,379,000,000
Cumulative effect of change in accounting principle										$ (33,000,000)		$ (47,000,000)	[2]
Ending balance		$ 28,210,000,000	$ 27,018,000,000	$ 26,377,000,000	$ 25,769,000,000	$ 25,171,000,000	$ 24,730,000,000	$ 28,210,000,000	$ 25,769,000,000

[1] See Note 2 to the consolidated financial statements for discussion regarding the adoption of accounting standards during the first quarter of fiscal year 2020.

[2] The cumulative effect of change in accounting principle during the first quarter of fiscal year 2019 resulted from the adoption of accounting guidance that requires equity investments (except those accounted for under the equity method of accounting or those that result in consolidation of the investee) to be measured at fair value with changes in fair value recognized in net income. As a result of the adoption, the Company reclassified $47 million from accumulated other comprehensive loss to the opening balance of retained earnings as of April 28, 2018.