Special Charges and Certain Litigation Charges, Net Certain Litigation Charges, Net (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended		3 Months Ended	9 Months Ended	3 Months Ended		9 Months Ended
	Jan. 24, 2014	Jan. 25, 2013	Jan. 24, 2014	Jan. 25, 2013	Oct. 26, 2012 Litigation with Edwards	Jan. 25, 2013 Litigation with Edwards	Jan. 24, 2014 Patent And Other Matters Litigation	Jan. 25, 2013 Patent And Other Matters Litigation	Jan. 24, 2014 Patent And Other Matters Litigation	Jan. 24, 2014 Patent And Other Matters Litigation Patent Litigation	Jan. 24, 2014 Patent And Other Matters Litigation Other Matters
Loss Contingencies [Line Items]
Certain litigation charges, net	$ 0	$ 0	$ 24	$ 245	$ 245	$ 245	$ 0	$ 0	$ 24	$ 12	$ 12