Retirement Benefit Plans (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Jan. 23, 2015	Jan. 24, 2014	Jan. 23, 2015	Jan. 24, 2014
U.S. Pension Benefits
Net Periodic Benefit Cost
Service cost	$ 26	$ 27	$ 78	$ 81
Interest cost	26	24	78	72
Expected return on plan assets	(39)	(35)	(117)	(105)
Amortization of net actuarial loss	16	21	48	63
Net periodic benefit cost	29	37	87	111
Non-U.S. Pension Benefits
Net Periodic Benefit Cost
Service cost	15	13	45	41
Interest cost	8	7	24	21
Expected return on plan assets	(10)	(8)	(30)	(26)
Amortization of net actuarial loss	3	3	9	7
Net periodic benefit cost	16	15	48	43
Post-Retirement Benefits
Net Periodic Benefit Cost
Service cost	5	5	15	15
Interest cost	4	4	12	10
Expected return on plan assets	(6)	(5)	(18)	(15)
Amortization of net actuarial loss	0	0	0	0
Net periodic benefit cost	$ 3	$ 4	$ 9	$ 10