CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended		6 Months Ended
	Sep. 30, 2020	Sep. 30, 2019	Sep. 30, 2020	Sep. 30, 2019
Income Statement [Abstract]
Revenues	$ 60,808	$ 57,616	$ 116,487	$ 113,344
Cost of sales	(57,808)	(54,749)	(110,787)	(107,690)
Gross profit	3,000	2,867	5,700	5,654
Operating expenses	(2,237)	(2,196)	(4,203)	(4,326)
Goodwill impairment charges	(69)	0	(69)	0
Restructuring, impairment, and related charges	(60)	(45)	(116)	(68)
Total operating expenses	(2,366)	(2,241)	(4,388)	(4,394)
Operating income	634	626	1,312	1,260
Other income (expense), net	71	(78)	98	(41)
Equity earnings and charges from investment in Change Healthcare Joint Venture	0	(1,454)	0	(1,450)
Interest expense	(50)	(64)	(110)	(120)
Income (loss) from continuing operations before income taxes	655	(970)	1,300	(351)
Income tax benefit (expense)	(28)	294	(178)	158
Income (loss) from continuing operations	627	(676)	1,122	(193)
Loss from discontinued operations, net of tax	0	(1)	(1)	(7)
Net income (loss)	627	(677)	1,121	(200)
Net income attributable to noncontrolling interests	(50)	(53)	(100)	(107)
Net income (loss) attributable to McKesson Corporation	$ 577	$ (730)	$ 1,021	$ (307)
Diluted
Continuing operations (in dollars per share)	$ 3.54	$ (3.99)	$ 6.26	$ (1.62)
Discontinued operations (in dollars per share)	0	0	0	(0.03)
Total (in dollars per share)	3.54	(3.99)	6.26	(1.65)
Basic
Continuing operations (in dollars per share)	3.56	(3.99)	6.31	(1.62)
Discontinued operations (in dollars per share)	0	0	(0.01)	(0.03)
Total (in dollars per share)	$ 3.56	$ (3.99)	$ 6.30	$ (1.65)
Weighted-average common shares outstanding
Diluted (in shares)	163	183	163	185
Basic (in shares)	162	183	162	185