CONSOLIDATED STATEMENTS OF STOCKHOLDERS’ EQUITY (DEFICIT) - USD ($) shares in Millions, $ in Millions	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Loss	Treasury	Noncontrolling Interests
Beginning balance, common stock (in shares) at Mar. 31, 2021		273
Beginning balance, treasury common stock (shares) at Mar. 31, 2021						(115)
Beginning balance at Mar. 31, 2021	$ 175	$ 2	$ 6,925	$ 8,202	$ (1,480)	$ (13,670)	$ 196
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under employee plans, net of forfeitures (in shares)		2
Issuance of shares under employee plans, net of forfeitures	149		220			$ (71)
Share-based compensation	154		154
Repurchase of common stock (in shares)						(15)
Repurchase of common stock	(3,508)		(204)			$ (3,304)
Net income	1,279			1,114			165
Other comprehensive income (loss)	112				116		(4)
Cash dividends declared	(279)			(279)
Payments to noncontrolling interests	(155)						(155)
Exercise of put right by noncontrolling shareholders of McKesson Europe AG	8		178		(170)
Reclassification of McKesson Europe AG redeemable noncontrolling interests	287						287
Reclassification of recurring compensation to other accrued liabilities	(7)						(7)
Other	(7)		2	(7)			(2)
Ending balance common stock (in shares) at Mar. 31, 2022		275
Ending balance, treasury common stock (shares) at Mar. 31, 2022						(130)
Ending balance at Mar. 31, 2022	(1,792)	$ 2	7,275	9,030	(1,534)	$ (17,045)	480
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under employee plans, net of forfeitures (in shares)		2
Issuance of shares under employee plans, net of forfeitures	4	$ 1	163			$ (160)
Share-based compensation	161		161
Repurchase of common stock (in shares)						(11)
Repurchase of common stock	(3,665)		127			$ (3,792)
Net income	3,722			3,560			162
Other comprehensive income (loss)	673				629		44
Cash dividends declared	(296)			(296)
Payments to noncontrolling interests	(150)						(150)
Reclassification of recurring compensation to other accrued liabilities	(5)						(5)
Formation of SCRI Oncology, LLC	247		22				225
Derecognition of noncontrolling interests in McKesson Europe AG	(382)						(382)
Other	(7)		(1)	1			(7)
Ending balance common stock (in shares) at Mar. 31, 2023		277
Ending balance, treasury common stock (shares) at Mar. 31, 2023						(141)
Ending balance at Mar. 31, 2023	(1,490)	$ 3	7,747	12,295	(905)	$ (20,997)	367
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Issuance of shares under employee plans, net of forfeitures (in shares)		1
Issuance of shares under employee plans, net of forfeitures	17		116			$ (99)
Share-based compensation	182		182
Repurchase of common stock (in shares)						(7)
Repurchase of common stock	(3,023)					$ (3,023)
Net income	3,160			3,002			158
Other comprehensive income (loss)	24				24
Cash dividends declared	(320)			(320)
Payments to noncontrolling interests	(152)						(152)
Other	3		3	1			(1)
Ending balance common stock (in shares) at Mar. 31, 2024		278
Ending balance, treasury common stock (shares) at Mar. 31, 2024						(148)
Ending balance at Mar. 31, 2024	$ (1,599)	$ 3	$ 8,048	$ 14,978	$ (881)	$ (24,119)	$ 372