Accumulated Other Comprehensive (Loss) Income and Supplemental Equity Disclosure - Changes in AOCI (Details) - USD ($)	3 Months Ended		6 Months Ended
	Oct. 27, 2017	Oct. 28, 2016	Oct. 27, 2017	Oct. 28, 2016
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance			$ 50,416,000,000	$ 52,063,000,000
Other comprehensive (loss) income	$ (136,000,000)	$ (304,000,000)	553,000,000	(460,000,000)
Balance	51,578,000,000	50,293,000,000	51,578,000,000	50,293,000,000
Unrealized Gain (Loss) on Available-for-Sale Securities
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance			(69,000,000)	(107,000,000)
Other comprehensive income (loss) before reclassifications			63,000,000	88,000,000
Reclassifications			(8,000,000)	(13,000,000)
Other comprehensive (loss) income			55,000,000	75,000,000
Balance	(14,000,000)	(32,000,000)	(14,000,000)	(32,000,000)
Other Comprehensive Income (Loss), Tax [Abstract]
Other comprehensive income (loss) before reclassifications, tax expense (benefit)			27,000,000	44,000,000
Reclassifications, tax expense (benefit)			4,000,000	7,000,000
Cumulative Translation Adjustment
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance			(1,452,000,000)	(474,000,000)
Other comprehensive income (loss) before reclassifications			662,000,000	(686,000,000)
Reclassifications			(34,000,000)	0
Other comprehensive (loss) income			628,000,000	(686,000,000)
Balance	(824,000,000)	(1,160,000,000)	(824,000,000)	(1,160,000,000)
Net Change in Retirement Obligations
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance			(1,129,000,000)	(1,197,000,000)
Other comprehensive income (loss) before reclassifications			(19,000,000)	0
Reclassifications			33,000,000	44,000,000
Other comprehensive (loss) income			14,000,000	44,000,000
Balance	(1,115,000,000)	(1,153,000,000)	(1,115,000,000)	(1,153,000,000)
Other Comprehensive Income (Loss), Tax [Abstract]
Other comprehensive income (loss) before reclassifications, tax expense (benefit)			(4,000,000)	0
Reclassifications, tax expense (benefit)			15,000,000	10,000,000
Unrealized Gain (Loss) on Derivative Financial Instruments
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance			37,000,000	(90,000,000)
Other comprehensive income (loss) before reclassifications			(140,000,000)	118,000,000
Reclassifications			(4,000,000)	(11,000,000)
Other comprehensive (loss) income			(144,000,000)	107,000,000
Balance	(107,000,000)	17,000,000	(107,000,000)	17,000,000
Other Comprehensive Income (Loss), Tax [Abstract]
Other comprehensive income (loss) before reclassifications, tax expense (benefit)			(81,000,000)	66,000,000
Reclassifications, tax expense (benefit)			4,000,000	8,000,000
Total Accumulated Other Comprehensive (Loss) Income
AOCI Including Portion Attributable to Noncontrolling Interest, Net of Tax [Roll Forward]
Balance			(2,613,000,000)	(1,868,000,000)
Other comprehensive income (loss) before reclassifications			566,000,000	(480,000,000)
Reclassifications			(13,000,000)	20,000,000
Other comprehensive (loss) income			553,000,000	(460,000,000)
Balance	$ (2,060,000,000)	$ (2,328,000,000)	$ (2,060,000,000)	$ (2,328,000,000)