Revenue - Disaggregation of Net Sales by Market Geography for Each Segment (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Oct. 26, 2018	Oct. 27, 2017	Oct. 26, 2018	Oct. 27, 2017
Disaggregation of Revenue [Line Items]
Net sales	$ 7,481	$ 7,050	$ 14,865	$ 14,440
U.S.
Disaggregation of Revenue [Line Items]
Net sales	4,045	3,734	7,909	7,776
Non-U.S. Developed Markets
Disaggregation of Revenue [Line Items]
Net sales	2,282	2,241	4,688	4,554
Emerging Markets
Disaggregation of Revenue [Line Items]
Net sales	1,154	1,075	2,268	2,110
Cardiac and Vascular Group
Disaggregation of Revenue [Line Items]
Net sales	2,858	2,773	5,669	5,419
Cardiac and Vascular Group | U.S.
Disaggregation of Revenue [Line Items]
Net sales	1,482	1,423	2,871	2,756
Cardiac and Vascular Group | Non-U.S. Developed Markets
Disaggregation of Revenue [Line Items]
Net sales	895	895	1,842	1,782
Cardiac and Vascular Group | Emerging Markets
Disaggregation of Revenue [Line Items]
Net sales	481	455	956	881
Minimally Invasive Therapies Group
Disaggregation of Revenue [Line Items]
Net sales	2,047	1,952	4,099	4,438
Minimally Invasive Therapies Group | U.S.
Disaggregation of Revenue [Line Items]
Net sales	872	795	1,729	2,040
Minimally Invasive Therapies Group | Non-U.S. Developed Markets
Disaggregation of Revenue [Line Items]
Net sales	772	783	1,600	1,648
Minimally Invasive Therapies Group | Emerging Markets
Disaggregation of Revenue [Line Items]
Net sales	403	374	770	750
Restorative Therapies Group
Disaggregation of Revenue [Line Items]
Net sales	1,993	1,863	3,942	3,672
Restorative Therapies Group | U.S.
Disaggregation of Revenue [Line Items]
Net sales	1,357	1,258	2,651	2,479
Restorative Therapies Group | Non-U.S. Developed Markets
Disaggregation of Revenue [Line Items]
Net sales	412	394	840	788
Restorative Therapies Group | Emerging Markets
Disaggregation of Revenue [Line Items]
Net sales	224	211	451	405
Diabetes Group
Disaggregation of Revenue [Line Items]
Net sales	583	462	1,155	911
Diabetes Group | U.S.
Disaggregation of Revenue [Line Items]
Net sales	334	258	658	501
Diabetes Group | Non-U.S. Developed Markets
Disaggregation of Revenue [Line Items]
Net sales	203	169	406	336
Diabetes Group | Emerging Markets
Disaggregation of Revenue [Line Items]
Net sales	$ 46	$ 35	$ 91	$ 74