Segment Information (Revenue by Reportable Segment) (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2019	Jun. 30, 2018	Jun. 30, 2017
Segment Reporting Information [Line Items]
Total revenue	$ 37,353	$ 35,228	$ 37,740	$ 35,213	$ 35,349	$ 33,633	$ 35,186	$ 32,641	$ 145,534	$ 136,809	$ 129,976
Non-US [Member]
Segment Reporting Information [Line Items]
Total revenue									4,071	4,283	4,970
United States
Segment Reporting Information [Line Items]
Total revenue									141,479	132,539	125,017
Operating Segments
Segment Reporting Information [Line Items]
Total revenue									145,550	136,822	129,987
Operating Segments | Pharmaceutical
Segment Reporting Information [Line Items]
Total revenue									129,917	121,241	116,463
Operating Segments | Medical
Segment Reporting Information [Line Items]
Total revenue									15,633	15,581	13,524
Corporate
Segment Reporting Information [Line Items]
Total revenue									(16)	$ (13)	$ (11)
Pharmaceutical Distribution and Specialty [Member] | Operating Segments | Pharmaceutical
Segment Reporting Information [Line Items]
Total revenue									129,067
Nuclear Precision Health Services [Member] | Operating Segments | Pharmaceutical
Segment Reporting Information [Line Items]
Total revenue									850
Medical distribution and products [Member] | Operating Segments | Medical
Segment Reporting Information [Line Items]
Total revenue									13,833
Cardinal Health At Home Solutions [Member] | Operating Segments | Medical
Segment Reporting Information [Line Items]
Total revenue									$ 1,800