Earnings Per Share Attributable to Cardinal Health, Inc. (Reconciliation of Common Shares Used to Compute Basic and Diluted EPS) (Details) - USD ($) $ / shares in Units, shares in Millions, $ 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
Earnings Per Share [Abstract]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 194	$ 296	$ 281	$ 594	$ (1,166)	$ 255	$ 1,053	$ 117	$ 1,365	$ 259	$ 1,294
Net earnings attributable to noncontrolling interest	0	0	1	1	0	0	0	2	(2)	(3)	(6)
Net Income (Loss) Attributable to Parent	$ 194	$ 296	$ 280	$ 593	$ (1,166)	$ 255	$ 1,053	$ 115	$ 1,363	$ 256	$ 1,288
Weighted-average common shares–basic (in shares)									300	313	317
Effect of dilutive securities:
Employee stock options, restricted share units, and performance share units (in shares)									1	2	3
Weighted-average common shares–diluted (in shares)									301	315	320
Diluted earnings per common share attributable to Cardinal Health, Inc.:
Earnings Per Share, Basic									$ 4.55	$ 0.82	$ 4.06
Earnings Per Share, Diluted									$ 4.53	$ 0.81	$ 4.03