Redeemable Noncontrolling Interests and Noncontrolling Interests - Narrative (Details) shares in Millions, $ in Millions	3 Months Ended
	Jun. 30, 2022 USD ($)	Jun. 30, 2021 USD ($) shares	Dec. 31, 2014 € / shares
Noncontrolling Interest [Line Items]
Put right redemption price per share (in euros per share) | € / shares			€ 22.99
Put right value, interest rate spread (as a percent)			5.00%
Payments for purchase shares of McKesson Europe	$ 0	$ 1,031
Associated increase in Company's ownership interest on its equity		8
Reclassification of temporary equity to noncontrolling interest		(287)
Net income attributable to noncontrolling interests	41	47
Redeemable Noncontrolling Interest
Noncontrolling Interest [Line Items]
Net income attributable to noncontrolling interests		8
Decrease in noncontrolling interest		983
Reclassification of temporary equity to noncontrolling interest		287
Additional Paid-in Capital
Noncontrolling Interest [Line Items]
Associated increase in Company's ownership interest on its equity		178
Noncontrolling Interests
Noncontrolling Interest [Line Items]
Decrease in noncontrolling interest		0
Reclassification of temporary equity to noncontrolling interest		(287)
Net income attributable to noncontrolling interests	41	39
McKesson Europe Subsidiary
Noncontrolling Interest [Line Items]
Annual recurring dividend (in euro per share) | € / shares			€ 0.83
McKesson Europe Subsidiary
Noncontrolling Interest [Line Items]
Net income attributable to noncontrolling interests		8
Payments for purchase shares of McKesson Europe		$ 1,000
Shares purchased (in shares) | shares		34.5
Vantage and ClarusOne Sourcing Services LLC
Noncontrolling Interest [Line Items]
Net income attributable to noncontrolling interests	$ 41	$ 39