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, 2020	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2020	Jun. 30, 2019	Jun. 30, 2018
Earnings Per Share [Abstract]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ 657	$ 351	$ 220	$ (4,921)	$ 194	$ 296	$ 281	$ 594	$ (3,693)	$ 1,365	$ 259
Net earnings attributable to noncontrolling interest	(1)	1	0	1	0	0	1	1	(3)	(2)	(3)
Net Income (Loss) Attributable to Parent	$ 656	$ 350	$ 220	$ (4,922)	$ 194	$ 296	$ 280	$ 593	$ (3,696)	$ 1,363	$ 256
Weighted-average common shares–basic (in shares)									293	300	313
Effect of dilutive securities:
Employee stock options, restricted share units, and performance share units (in shares)									0	1	2
Weighted-average common shares–diluted (in shares)									293	301	315
Diluted earnings per common share attributable to Cardinal Health, Inc.:
Earnings Per Share, Basic									$ (12.61)	$ 4.55	$ 0.82
Earnings Per Share, Diluted									$ (12.61)	$ 4.53	$ 0.81