Restructuring Charges (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Jan. 23, 2015	Oct. 24, 2014	Jul. 25, 2014	Jul. 26, 2013	Apr. 26, 2013	Apr. 25, 2014
Fiscal Year 2013 Initiative [Member]
Changes in Restructuring Reserves
Beginning balance	$ 13	$ 16	$ 24
Restructuring Charges				18	192
Payments/write-downs	(2)	(3)	(6)
Restructuring Reserve, Accrual Adjustment			(2)
Ending balance	11	13	16
Fiscal Year 2013 Initiative [Member] | Employee Termination Costs
Changes in Restructuring Reserves
Beginning balance	13	16	23
Restructuring Charges					150
Payments/write-downs	(2)	(3)	(5)
Restructuring Reserve, Accrual Adjustment			(2)
Ending balance	11	13	16
Fiscal Year 2013 Initiative [Member] | Asset Write-downs
Changes in Restructuring Reserves
Restructuring Charges					13
Fiscal Year 2013 Initiative [Member] | Inventory write-offs
Changes in Restructuring Reserves
Restructuring Charges					10
Fiscal Year 2013 Initiative [Member] | Other Costs
Changes in Restructuring Reserves
Beginning balance	0	0	1
Payments/write-downs	0	0	(1)
Restructuring Reserve, Accrual Adjustment			0
Ending balance	0	0	0
Fiscal Year 2013 Initiative [Member] | Contract Termination Costs
Changes in Restructuring Reserves
Restructuring Charges				14	18
Fiscal Year 2013 Initiative [Member] | Other Restructuring [Member]
Changes in Restructuring Reserves
Restructuring Charges				4	11
Fiscal Year 2014 Initiative [Member]
Changes in Restructuring Reserves
Beginning balance	40	62	75
Restructuring Charges			38			116
Payments/write-downs	(10)	(22)	(45)
Restructuring Reserve, Accrual Adjustment			(6)
Ending balance	30	40	62			75
Fiscal Year 2014 Initiative [Member] | Employee Termination Costs
Changes in Restructuring Reserves
Beginning balance	27	42	64
Restructuring Charges			1			65
Payments/write-downs	(4)	(15)	(17)
Restructuring Reserve, Accrual Adjustment			(6)
Ending balance	23	27	42			64
Fiscal Year 2014 Initiative [Member] | Asset Write-downs
Changes in Restructuring Reserves
Beginning balance	0	0	0
Restructuring Charges			9			26
Payments/write-downs	0	0	(9)
Restructuring Reserve, Accrual Adjustment			0
Ending balance	0	0	0			0
Fiscal Year 2014 Initiative [Member] | Inventory write-offs
Changes in Restructuring Reserves
Restructuring Charges						10
Fiscal Year 2014 Initiative [Member] | Other Costs
Changes in Restructuring Reserves
Beginning balance	13	20	11
Restructuring Charges			28
Payments/write-downs	(6)	(7)	(19)
Restructuring Reserve, Accrual Adjustment			0
Ending balance	7	13	20
Fiscal Year 2014 Initiative [Member] | Contract Termination Costs
Changes in Restructuring Reserves
Restructuring Charges						3
Fiscal Year 2014 Initiative [Member] | Other Restructuring [Member]
Changes in Restructuring Reserves
Restructuring Charges						$ 22