CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Income Statement [Abstract]
Total Revenues	$ 56,208	$ 53,617	$ 161,890	$ 156,729
Cost of Sales	(53,238)	(50,902)	(153,337)	(148,620)
Gross Profit	2,970	2,715	8,553	8,109
Operating Expenses	(2,156)	(1,984)	(6,219)	(5,920)
Goodwill Impairment Charges	(21)	0	(591)	(350)
Restructuring and Asset Impairment Charges	(110)	(6)	(288)	(242)
Gain from Sale of Business	0	109	0	109
Total Operating Expenses	(2,287)	(1,881)	(7,098)	(6,403)
Operating Income	683	834	1,455	1,706
Other Income, Net	84	20	144	102
Loss from Equity Method Investment in Change Healthcare	(50)	(90)	(162)	(271)
Interest Expense	(67)	(67)	(194)	(204)
Income from Continuing Operations Before Income Taxes	650	697	1,243	1,333
Income Tax (Expense) Benefit	(123)	263	(245)	46
Income from Continuing Operations	527	960	998	1,379
(Loss) Income from Discontinued Operations, Net of Tax	(1)	1	1	3
Net Income	526	961	999	1,382
Net Income Attributable to Noncontrolling Interests	(57)	(58)	(169)	(169)
Net Income Attributable to McKesson Corporation	$ 469	$ 903	$ 830	$ 1,213
Diluted
Continuing operations (in dollars per share)	$ 2.41	$ 4.32	$ 4.17	$ 5.75
Discontinued operations (in dollars per share)	(0.01)	0.01	0.01	0.01
Total (in dollars per share)	2.40	4.33	4.18	5.76
Basic
Continuing operations (in dollars per share)	2.42	4.34	4.19	5.78
Discontinued operations (in dollars per share)	(0.01)	0.01	0.00	0.02
Total (in dollars per share)	2.41	4.35	4.19	5.80
Dividends declared per common share (in dollars per share)	$ 0.39	$ 0.34	$ 1.12	$ 0.96
Weighted Average Common Shares
Diluted (in shares)	195	208	199	210
Basic (in shares)	194	207	198	209