Segment Information (Revenue by Reportable Segment) (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2019	Mar. 31, 2018
Segment Reporting Information [Line Items]
Total revenue	$ 35,228	$ 33,633	$ 108,181	$ 101,460
Operating Segments
Segment Reporting Information [Line Items]
Total revenue	35,232	33,636	108,194	101,470
Operating Segments | Pharmaceutical
Segment Reporting Information [Line Items]
Total revenue	31,361	29,720	96,516	89,786
Operating Segments | Medical
Segment Reporting Information [Line Items]
Total revenue	3,871	3,916	11,678	11,684
Corporate
Segment Reporting Information [Line Items]
Total revenue	(4)	$ (3)	(13)	$ (10)
Pharmaceutical distribution and specialty [Member] | Operating Segments | Pharmaceutical
Segment Reporting Information [Line Items]
Total revenue	31,146		95,888
Nuclear Precision Health Services [Member] | Operating Segments | Pharmaceutical
Segment Reporting Information [Line Items]
Total revenue	215		628
Medical distribution and products [Member] | Operating Segments | Medical
Segment Reporting Information [Line Items]
Total revenue	3,431		10,339
Cardinal Health At Home [Member] | Operating Segments | Medical
Segment Reporting Information [Line Items]
Total revenue	$ 440		$ 1,339