Accumulated Other Comprehensive Loss (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Jan. 23, 2015		Jan. 24, 2014		Jan. 23, 2015		Jan. 24, 2014
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, beginning of period					$ (597)		$ (492)
Other comprehensive income (loss) before reclassifications, before tax					199		(180)
Tax expense					(181)		65
Other comprehensive income (loss) before reclassifications, net of tax					18		(115)
Reclassifications, before tax					(127)		(17)
Tax benefit (expense)					45		6
Reclassifications, net of tax					(82)		(11)
Other comprehensive (loss) income, net of tax	(155)		(51)		(64)		(126)
Accumulated other comprehensive loss, end of period	(661)		(618)		(661)		(618)
Unrealized Gain (Loss) on Available-for-Sale Securities
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, beginning of period					(6)		97
Other comprehensive income (loss) before reclassifications, before tax					110		(142)
Tax expense					(40)		51
Other comprehensive income (loss) before reclassifications, net of tax					70		(91)
Reclassifications, before tax					(134)		(56)
Tax benefit (expense)					47		20
Reclassifications, net of tax					(87)	[1]	(36)	[1]
Other comprehensive (loss) income, net of tax					(17)		(127)
Accumulated other comprehensive loss, end of period	(23)		(30)		(23)		(30)
Cumulative Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, beginning of period					218	[2]	205	[2]
Other comprehensive income (loss) before reclassifications, before tax					(332)	[2]	1	[2]
Tax expense					0	[2]	0	[2]
Other comprehensive income (loss) before reclassifications, net of tax					(332)	[2]	1	[2]
Reclassifications, before tax					0	[2]	0	[2]
Tax benefit (expense)					0	[2]	0	[2]
Reclassifications, net of tax					0	[2]	0	[2]
Other comprehensive (loss) income, net of tax					(332)	[2]	1	[2]
Accumulated other comprehensive loss, end of period	(114)	[2]	206	[2]	(114)	[2]	206	[2]
Net Change in Retirement Obligations
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, beginning of period					(765)		(852)
Other comprehensive income (loss) before reclassifications, before tax					24		(2)
Tax expense					0		0
Other comprehensive income (loss) before reclassifications, net of tax					24		(2)
Reclassifications, before tax					57		70
Tax benefit (expense)					(18)		(25)
Reclassifications, net of tax					39	[3]	45	[3]
Other comprehensive (loss) income, net of tax					63		43
Accumulated other comprehensive loss, end of period	(702)		(809)		(702)		(809)
Unrealized Gain (Loss) on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, beginning of period					(44)		58
Other comprehensive income (loss) before reclassifications, before tax					397		(37)
Tax expense					(141)		14
Other comprehensive income (loss) before reclassifications, net of tax					256		(23)
Reclassifications, before tax					(50)		(31)
Tax benefit (expense)					16		11
Reclassifications, net of tax					(34)	[4]	(20)	[4]
Other comprehensive (loss) income, net of tax					222		(43)
Accumulated other comprehensive loss, end of period	$ 178		$ 15		$ 178		$ 15

[1] Represents net realized gains on sales of available-for-sale securities that were reclassified from AOCI to other expense, net (see Note 6).

[2] Taxes are not provided on CTA as substantially all translation adjustments relate to earnings that are intended to be indefinitely reinvested outside the U.S.

[3] Includes net amortization of prior service costs and actuarial losses included in net periodic benefit cost (see Note 17).

[4] Relates to foreign currency cash flow hedges that were reclassified from AOCI to other expense, net or cost of products sold and forward starting interest rate derivative instruments that were reclassified from AOCI to interest expense, net (see Note 9).