Restructuring Charges, Net - Restructuring Reserve (Details) - USD ($) $ in Millions		3 Months Ended
	Jan. 26, 2015	Oct. 30, 2015	Jul. 31, 2015	Apr. 24, 2015
Cost Synergies Initiative [Member]
Restructuring Reserve [Roll Forward]
Beginning balance		$ 127	$ 143
Restructuring charges		86	67	$ 248
Payments/write-downs		(44)	(83)
Reversal of excess accrual		(13)
Ending balance		156	127	143
Cost Synergies Initiative [Member] | Employee Termination Costs [Member]
Restructuring Reserve [Roll Forward]
Beginning balance		112	136
Restructuring charges		64	52	213
Payments/write-downs		(28)	(76)
Reversal of excess accrual		(13)
Ending balance		135	112	136
Cost Synergies Initiative [Member] | Asset Write-downs [Member]
Restructuring Reserve [Roll Forward]
Beginning balance		0	0
Restructuring charges		10	0	28
Payments/write-downs		(10)	0
Reversal of excess accrual		0
Ending balance		0	0	0
Cost Synergies Initiative [Member] | Other Costs [Member]
Restructuring Reserve [Roll Forward]
Beginning balance		15	7
Restructuring charges		12	15	1
Payments/write-downs		(6)	(7)
Reversal of excess accrual		0
Ending balance		21	15	7
Covidien Initiative [Member]
Restructuring Reserve [Roll Forward]
Beginning balance		60	78
Payments/write-downs		(14)	(18)
Reversal of excess accrual				(5)
Ending balance	$ 103	46	60	78
Covidien Initiative [Member] | Employee Termination Costs [Member]
Restructuring Reserve [Roll Forward]
Beginning balance		48	61
Restructuring charges	76
Payments/write-downs		(8)	(13)
Ending balance		40	48	61
Covidien Initiative [Member] | Other Costs [Member]
Restructuring Reserve [Roll Forward]
Beginning balance		12	17
Restructuring charges	$ 27
Payments/write-downs		(6)	(5)
Ending balance		$ 6	$ 12	$ 17