Stock-Based Compensation (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Jul. 25, 2014	Jul. 26, 2013
Stock-based Compensation Expense by Component and Classification
Stock-based compensation expense	$ 34	$ 31
Income tax benefits	(9)	(8)
Total stock-based compensation expense, net of tax	25	23
Cost of Products Sold
Stock-based Compensation Expense by Component and Classification
Stock-based compensation expense	4	3
Research and Development Expense
Stock-based Compensation Expense by Component and Classification
Stock-based compensation expense	6	6
Selling, General and Administrative Expense
Stock-based Compensation Expense by Component and Classification
Stock-based compensation expense	24	22
Stock Options
Stock-based Compensation Expense by Component and Classification
Stock-based compensation expense	6	8
Restricted Stock Awards
Stock-based Compensation Expense by Component and Classification
Stock-based compensation expense	23	19
Employee Stock Purchase Plan
Stock-based Compensation Expense by Component and Classification
Stock-based compensation expense	$ 5	$ 4