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, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2017	Dec. 31, 2016	Sep. 30, 2016	Jun. 30, 2018	Jun. 30, 2017	Jun. 30, 2016
Earnings Per Share [Abstract]
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest	$ (1,166)	$ 255	$ 1,053	$ 117	$ 278	$ 382	$ 324	$ 310	$ 259	$ 1,294	$ 1,431
Net earnings attributable to noncontrolling interest	0	0	0	2	4	1	0	1	(3)	(6)	(4)
Net Income (Loss) Attributable to Parent	$ (1,166)	$ 255	$ 1,053	$ 115	$ 274	$ 381	$ 324	$ 309	$ 256	$ 1,288	$ 1,427
Weighted-average common shares–basic (in shares)									313	317	327
Effect of dilutive securities:
Employee stock options, restricted share units, and performance share units (in shares)									2	3	3
Weighted-average common shares–diluted (in shares)									315	320	330
Diluted earnings per common share attributable to Cardinal Health, Inc.:
Earnings Per Share, Basic									$ 0.82	$ 4.06	$ 4.36
Earnings Per Share, Diluted									$ 0.81	$ 4.03	$ 4.32