Accumulated Other Comprehensive Loss (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Jul. 25, 2014		Jul. 26, 2013
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, beginning of period	$ (597)		$ (492)
Other comprehensive income before reclassifications, before tax	167		(118)
Tax expense	(58)		42
Other comprehensive income before reclassifications, net of tax	109		(76)
Reclassifications, before tax	1		(10)
Tax benefit (expense)	(1)		2
Reclassifications, net of tax	0		(8)
Other comprehensive income, net of tax	109		(84)
Accumulated other comprehensive loss, end of period	(488)		(576)
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 before reclassifications, before tax	107		(131)
Tax expense	(39)		48
Other comprehensive income before reclassifications, net of tax	68		(83)
Reclassifications, before tax	(21)		(18)
Tax benefit (expense)	7		6
Reclassifications, net of tax	(14)	[1]	(12)	[1]
Other comprehensive income, net of tax	54		(95)
Accumulated other comprehensive loss, end of period	48		2
Cumulative Translation Adjustments
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, beginning of period	218	[2]	205	[2]
Other comprehensive income before reclassifications, before tax	1	[2]	(5)	[2]
Tax expense	0	[2]	0	[2]
Other comprehensive income before reclassifications, net of tax	1	[2]	(5)	[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 income, net of tax	1	[2]	(5)	[2]
Accumulated other comprehensive loss, end of period	219	[2]	200	[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 before reclassifications, before tax	4		0
Tax expense	0		0
Other comprehensive income before reclassifications, net of tax	4		0
Reclassifications, before tax	19		23
Tax benefit (expense)	(6)		(9)
Reclassifications, net of tax	13	[3]	14	[3]
Other comprehensive income, net of tax	17		14
Accumulated other comprehensive loss, end of period	(748)		(838)
Unrealized Gain (Loss) on Derivatives
Accumulated Other Comprehensive Income (Loss) [Line Items]
Accumulated other comprehensive loss, beginning of period	(44)		58
Other comprehensive income before reclassifications, before tax	55		18
Tax expense	(19)		(6)
Other comprehensive income before reclassifications, net of tax	36		12
Reclassifications, before tax	3		(15)
Tax benefit (expense)	(2)		5
Reclassifications, net of tax	1	[4]	(10)	[4]
Other comprehensive income, net of tax	37		2
Accumulated other comprehensive loss, end of period	$ (7)		$ 60

[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).