Revenue - Disaggregation of Net Sales by Market Geography for Each Segment (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Jan. 24, 2020	Jan. 25, 2019	Jan. 24, 2020	Jan. 25, 2019
Disaggregation of Revenue [Line Items]
Net sales	$ 7,717	$ 7,546	$ 22,916	$ 22,411
U.S.
Disaggregation of Revenue [Line Items]
Net sales	4,021	4,001	12,068	11,910
Non-U.S. Developed Markets
Disaggregation of Revenue [Line Items]
Net sales	2,377	2,368	7,069	7,056
Emerging Markets
Disaggregation of Revenue [Line Items]
Net sales	1,318	1,177	3,778	3,445
Cardiac and Vascular Group
Disaggregation of Revenue [Line Items]
Net sales	2,819	2,786	8,464	8,455
Cardiac and Vascular Group | U.S.
Disaggregation of Revenue [Line Items]
Net sales	1,366	1,369	4,182	4,240
Cardiac and Vascular Group | Non-U.S. Developed Markets
Disaggregation of Revenue [Line Items]
Net sales	915	924	2,735	2,766
Cardiac and Vascular Group | Emerging Markets
Disaggregation of Revenue [Line Items]
Net sales	538	493	1,547	1,449
Minimally Invasive Therapies Group
Disaggregation of Revenue [Line Items]
Net sales	2,176	2,124	6,418	6,223
Minimally Invasive Therapies Group | U.S.
Disaggregation of Revenue [Line Items]
Net sales	934	930	2,769	2,659
Minimally Invasive Therapies Group | Non-U.S. Developed Markets
Disaggregation of Revenue [Line Items]
Net sales	791	796	2,364	2,396
Minimally Invasive Therapies Group | Emerging Markets
Disaggregation of Revenue [Line Items]
Net sales	451	398	1,285	1,168
Restorative Therapies Group
Disaggregation of Revenue [Line Items]
Net sales	2,111	2,026	6,235	5,968
Restorative Therapies Group | U.S.
Disaggregation of Revenue [Line Items]
Net sales	1,409	1,354	4,187	4,005
Restorative Therapies Group | Non-U.S. Developed Markets
Disaggregation of Revenue [Line Items]
Net sales	436	435	1,278	1,275
Restorative Therapies Group | Emerging Markets
Disaggregation of Revenue [Line Items]
Net sales	266	237	770	688
Diabetes Group
Disaggregation of Revenue [Line Items]
Net sales	610	610	1,798	1,765
Diabetes Group | U.S.
Disaggregation of Revenue [Line Items]
Net sales	312	348	930	1,006
Diabetes Group | Non-U.S. Developed Markets
Disaggregation of Revenue [Line Items]
Net sales	236	213	693	619
Diabetes Group | Emerging Markets
Disaggregation of Revenue [Line Items]
Net sales	$ 63	$ 49	$ 176	$ 140