Accumulated Other Comprehensive Income and Supplemental Equity Disclosure - Changes in AOCI (Details) - USD ($)	3 Months Ended
	Jul. 27, 2018	Jul. 28, 2017	Apr. 27, 2018
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	$ 50,822,000,000	$ 50,416,000,000
Other comprehensive income (loss) before reclassifications	(615,000,000)	694,000,000
Reclassifications	31,000,000	(5,000,000)
Other comprehensive (loss) income	(584,000,000)	689,000,000
Cumulative effect of change in accounting principle			$ 296,000,000
Balance	50,329,000,000	50,787,000,000
Unrealized (Loss) Gain on Available-for-Sale Securities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	(194,000,000)	(69,000,000)
Other comprehensive income (loss) before reclassifications	0	39,000,000
Reclassifications	0	(9,000,000)
Other comprehensive (loss) income	0	30,000,000
Cumulative effect of change in accounting principle			47,000,000
Balance	(147,000,000)	(39,000,000)
Other Comprehensive Income (Loss), Tax [Abstract]
Other comprehensive income (loss) before reclassifications, tax expense (benefit)	0	17,000,000
Reclassifications, tax expense (benefit)	0	4,000,000
Cumulative Translation Adjustment
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	(268,000,000)	(1,452,000,000)
Other comprehensive income (loss) before reclassifications	(824,000,000)	831,000,000
Reclassifications	0	0
Other comprehensive (loss) income	(824,000,000)	831,000,000
Cumulative effect of change in accounting principle			0
Balance	(1,092,000,000)	(621,000,000)
Other Comprehensive Income (Loss), Tax [Abstract]
Other comprehensive income (loss) before reclassifications, tax expense (benefit)	(5,000,000)
Net Change in Retirement Obligations
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	(1,117,000,000)	(1,129,000,000)
Other comprehensive income (loss) before reclassifications	0	(17,000,000)
Reclassifications	27,000,000	16,000,000
Other comprehensive (loss) income	27,000,000	(1,000,000)
Cumulative effect of change in accounting principle			0
Balance	(1,090,000,000)	(1,130,000,000)
Other Comprehensive Income (Loss), Tax [Abstract]
Other comprehensive income (loss) before reclassifications, tax expense (benefit)	0	(4,000,000)
Reclassifications, tax expense (benefit)	5,000,000	8,000,000
Unrealized (Loss) Gain on Derivative Financial Instruments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	(207,000,000)	37,000,000
Other comprehensive income (loss) before reclassifications	209,000,000	(159,000,000)
Reclassifications	4,000,000	(12,000,000)
Other comprehensive (loss) income	213,000,000	(171,000,000)
Cumulative effect of change in accounting principle			0
Balance	6,000,000	(134,000,000)
Other Comprehensive Income (Loss), Tax [Abstract]
Other comprehensive income (loss) before reclassifications, tax expense (benefit)	60,000,000	(91,000,000)
Reclassifications, tax expense (benefit)	(1,000,000)	8,000,000
Total Accumulated Other Comprehensive (Loss) Income
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance	(1,786,000,000)	(2,613,000,000)
Cumulative effect of change in accounting principle			$ 47,000,000
Balance	$ (2,323,000,000)	$ (1,924,000,000)