CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2021	Sep. 30, 2020	Sep. 30, 2021	Sep. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 310	$ 627	$ 843	$ 1,121
Other comprehensive income (loss), net of tax
Foreign currency translation adjustments	(48)	41	(24)	74
Unrealized gains (losses) on cash flow hedges	8	(19)	8	(24)
Changes in retirement-related benefit plans	2	(9)	4	(8)
Other comprehensive income (loss), net of tax	(38)	13	(12)	42
Comprehensive income	272	640	831	1,163
Comprehensive (income) loss attributable to noncontrolling interests	(43)	75	(93)	(36)
Comprehensive income attributable to McKesson Corporation	$ 229	$ 715	$ 738	$ 1,127