Segment Information (Revenue by Reportable Segment) (Details) - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Segment Reporting Information [Line Items]
Total revenue	$ 37,740	$ 35,186	$ 72,953	$ 67,827
Operating Segments
Segment Reporting Information [Line Items]
Total revenue	37,746	35,190	72,962	67,834
Operating Segments | Pharmaceutical
Segment Reporting Information [Line Items]
Total revenue	33,740	31,146	65,155	60,066
Operating Segments | Medical
Segment Reporting Information [Line Items]
Total revenue	4,006	4,044	7,807	7,768
Corporate
Segment Reporting Information [Line Items]
Total revenue	(6)	$ (4)	(9)	$ (7)
Pharmaceutical distribution and specialty [Member] | Operating Segments | Pharmaceutical
Segment Reporting Information [Line Items]
Total revenue	33,534		64,742
Nuclear Precision Health Services [Member] | Operating Segments | Pharmaceutical
Segment Reporting Information [Line Items]
Total revenue	206		413
Medical distribution and products [Member] | Operating Segments | Medical
Segment Reporting Information [Line Items]
Total revenue	3,527		6,907
Cardinal Health At Home [Member] | Operating Segments | Medical
Segment Reporting Information [Line Items]
Total revenue	$ 479		$ 900