Earnings Per Share (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended				9 Months Ended				3 Months Ended		9 Months Ended
	Jan. 25, 2013		Jan. 27, 2012		Jan. 25, 2013		Jan. 27, 2012		Jan. 25, 2013 Stock Options	Jan. 27, 2012 Stock Options	Jan. 25, 2013 Stock Options	Jan. 27, 2012 Stock Options	Jan. 25, 2013 2013 Senior Convertible Notes	Apr. 27, 2012 2013 Senior Convertible Notes	Jan. 27, 2012 2013 Senior Convertible Notes	Apr. 30, 2006 2013 Senior Convertible Notes
Numerator:
Earnings from continuing operations	$ 988		$ 845		$ 2,498		$ 2,527
Earnings from discontinued operations	0		90		0		99
Net earnings	988		935		2,498		2,626
Denominator
Basic weighted average shares outstanding (shares)	1,012.5		1,054.4		1,020.7		1,058.5
Effect of dilutive securities:
Employee stock options (shares)	3.0		0.8		2.3		0.7
Employee restricted stock units (shares)	5.4		4.8		5.6		4.7
Other (shares)	0.1		0.2		0.1		0.2
Diluted weighted average shares outstanding (shares)	1,021.0		1,060.2		1,028.7		1,064.1
Basic earnings per share:
Earnings from continuing operations (usd per share)	$ 0.98		$ 0.80		$ 2.45		$ 2.39
Earnings from discontinued operations (usd per share)	$ 0.00		$ 0.09		$ 0.00		$ 0.09
Net earnings (usd per share)	$ 0.98		$ 0.89		$ 2.45		$ 2.48
Diluted earnings per share:
Earnings from continuing operations (usd per share)	$ 0.97		$ 0.80		$ 2.43		$ 2.37
Earnings from discontinued operations (usd per share)	$ 0.00		$ 0.08		$ 0.00		$ 0.09
Net earnings (usd per share)	$ 0.97	[1]	$ 0.88	[1]	$ 2.43	[1]	$ 2.47	[1]
Number of shares excluded from computation of earnings per share									40	53	40	53
Principal amount													$ 2,200	$ 2,200	$ 2,200	$ 2,200

[1] All earnings per share amounts have been rounded to the nearest $0.01, and therefore, may not sum.