Goodwill and Other Intangible Assets, Net (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Oct. 24, 2014	Oct. 25, 2013	Oct. 24, 2014	Oct. 25, 2013	Apr. 25, 2014
The changes in the carrying amount of goodwill
Beginning balance			$ 10,593
Goodwill as a result of acquisitions			453
Goodwill, Purchase Accounting Adjustments			1
Currency adjustments, net			(23)
Ending balance	11,024		11,024
Balance of intangible assets, excluding goodwill
Intangible Assets, Gross (Excluding Goodwill)	4,852		4,852		4,584
Accumulated amortization	(2,415)		(2,415)		(2,298)
Carrying value	2,299		2,299
Intangible Assets, Net (Excluding Goodwill)	2,437		2,437		2,286
Amortization expense	89	88	176	174
Estimated aggregate amortization expense
Remaining 2015	191		191
2016	347		347
2017	325		325
2018	310		310
2019	265		265
2020	217		217
Thereafter	644		644
Purchased Technology and Patents
Balance of intangible assets, excluding goodwill
Original cost	3,978		3,978		3,857
Accumulated amortization	(2,019)		(2,019)		(1,878)
Carrying value	1,959		1,959		1,979
Trademarks and Tradenames
Balance of intangible assets, excluding goodwill
Original cost	428		428		408
Accumulated amortization	(340)		(340)		(332)
Carrying value	88		88		76
Other
Balance of intangible assets, excluding goodwill
Original cost	308		308		200
Accumulated amortization	(56)		(56)		(88)
Carrying value	252		252		112
Cardiac and Vascular Group
The changes in the carrying amount of goodwill
Beginning balance			2,881
Goodwill as a result of acquisitions			234
Goodwill, Purchase Accounting Adjustments			1
Currency adjustments, net			(14)
Ending balance	3,102		3,102
Restorative Therapies Group
The changes in the carrying amount of goodwill
Beginning balance			6,368
Goodwill as a result of acquisitions			219
Goodwill, Purchase Accounting Adjustments			0
Currency adjustments, net			(9)
Ending balance	6,578		6,578
Diabetes Group [Member]
The changes in the carrying amount of goodwill
Beginning balance			1,344
Goodwill as a result of acquisitions			0
Goodwill, Purchase Accounting Adjustments			0
Currency adjustments, net			0
Ending balance	1,344		1,344
In Process Research and Development [Member]
Balance of intangible assets, excluding goodwill
Indefinite-Lived Intangible Assets (Excluding Goodwill)	$ 138		$ 138		$ 119