Segment Information (Revenue by Reportable Segment) (Details) - USD ($) $ in Millions	3 Months Ended
	Sep. 30, 2018	Sep. 30, 2017
Segment Reporting Information [Line Items]
Total revenue	$ 35,213	$ 32,641
Operating Segments
Segment Reporting Information [Line Items]
Total revenue	39,018	32,644
Operating Segments | Pharmaceutical
Segment Reporting Information [Line Items]
Total revenue	31,416	28,920
Operating Segments | Medical
Segment Reporting Information [Line Items]
Total revenue	3,801	3,724
Corporate
Segment Reporting Information [Line Items]
Total revenue	(4)	$ (3)
Nuclear Precision Health Services [Member] | Operating Segments | Pharmaceutical
Segment Reporting Information [Line Items]
Total revenue	207
Pharmaceutical distribution and specialty [Member] | Operating Segments | Pharmaceutical
Segment Reporting Information [Line Items]
Total revenue	31,209
Medical distribution and products [Member] | Operating Segments | Medical
Segment Reporting Information [Line Items]
Total revenue	3,380
Cardinal Health At Home [Member] | Operating Segments | Medical
Segment Reporting Information [Line Items]
Total revenue	$ 421