Redeemable Noncontrolling Interests and Noncontrolling Interests - Schedule of Changes in Redeemable Noncontrolling Interests and Noncontrolling Interests (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2022	Jun. 30, 2021
Noncontrolling Interests
Beginning balance	$ 480
Net income attributable to noncontrolling interests	41	$ 47
Payments to noncontrolling interests	(36)	(39)
Ending balance	532
Redeemable Noncontrolling Interests
Payments to noncontrolling interests	(36)	(39)
Reclassification of McKesson Europe AG redeemable noncontrolling interests		287
Noncontrolling Interests
Noncontrolling Interests
Beginning balance	480	196
Net income attributable to noncontrolling interests	41	39
Other comprehensive income	50	0
Reclassification of recurring compensation to other accrued liabilities	(2)	0
Payments to noncontrolling interests	(36)	(39)
Other	(1)	1
Ending balance	532	484
Redeemable Noncontrolling Interests
Other comprehensive income	50	0
Reclassification of recurring compensation to other accrued liabilities	(2)	0
Payments to noncontrolling interests	(36)	(39)
Exercises of Put Right		0
Reclassification of McKesson Europe AG redeemable noncontrolling interests		287
Other	$ 1	(1)
Redeemable Noncontrolling Interest
Noncontrolling Interests
Other comprehensive income		3
Reclassification of recurring compensation to other accrued liabilities		(8)
Payments to noncontrolling interests		0
Other		3
Redeemable Noncontrolling Interests
Beginning balance		1,271
Net income attributable to noncontrolling interests		8
Other comprehensive income		3
Reclassification of recurring compensation to other accrued liabilities		(8)
Payments to noncontrolling interests		0
Exercises of Put Right		(983)
Reclassification of McKesson Europe AG redeemable noncontrolling interests		(287)
Other		(3)
Ending balance		$ 7