Retirement Benefit Plans (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			9 Months Ended
	Jan. 25, 2013	Jan. 27, 2012		Jan. 25, 2013	Jan. 27, 2012
U.S. Pension Benefits
Net Periodic Benefit Cost
Service cost	$ 26	$ 23	[1]	$ 78	$ 69	[1]
Interest cost	23	22	[1]	69	66	[1]
Expected return on plan assets	(32)	(30)	[1]	(96)	(90)	[1]
Amortization of net actuarial loss	18	11	[1]	54	33	[1]
Net periodic benefit cost	35	26	[1]	105	78	[1]
Non-U.S. Pension Benefits
Net Periodic Benefit Cost
Service cost	11	11	[1]	33	33	[1]
Interest cost	7	7	[1]	21	21	[1]
Expected return on plan assets	(8)	(9)	[1]	(24)	(27)	[1]
Amortization of net actuarial loss	2	1	[1]	6	3	[1]
Net periodic benefit cost	12	10	[1]	36	30	[1]
Post-Retirement Benefits
Net Periodic Benefit Cost
Service cost	5	5	[1]	15	15	[1]
Interest cost	4	4	[1]	12	12	[1]
Expected return on plan assets	(4)	(4)	[1]	(12)	(12)	[1]
Amortization of net actuarial loss	1	1	[1]	3	3	[1]
Net periodic benefit cost	$ 6	$ 6	[1]	$ 18	$ 18	[1]

[1] Components of the net periodic benefit cost for the three and nine months ended January 27, 2012 include balances related to Physio-Control.