CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2021	Jun. 30, 2020
Statement of Comprehensive Income [Abstract]
Net income	$ 533	$ 494
Other comprehensive income (loss), net of tax
Foreign currency translation adjustments	24	33
Unrealized losses on cash flow hedges	0	(5)
Changes in retirement-related benefit plans	2	1
Other comprehensive income (loss), net of tax	26	29
Comprehensive income	559	523
Comprehensive income attributable to noncontrolling interests	(50)	(111)
Comprehensive income attributable to McKesson Corporation	$ 509	$ 412