CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS (Unaudited) - USD ($) shares in Millions, $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2017	Dec. 31, 2016
Income Statement [Abstract]
Revenues	$ 53,617	$ 50,130	$ 156,729	$ 149,820
Cost of Sales	(50,902)	(47,318)	(148,620)	(141,345)
Gross Profit	2,715	2,812	8,109	8,475
Operating Expenses	(1,984)	(1,981)	(5,920)	(5,802)
Gain from Sale of Business	109	0	109	0
Goodwill Impairment Charges	0	0	(350)	(290)
Restructuring and Asset Impairment Charges	(6)	0	(242)	0
Operating Income	834	831	1,706	2,383
Other Income, Net	20	23	102	65
Loss from Equity Method Investment in Change Healthcare	(90)	0	(271)	0
Interest Expense	(67)	(74)	(204)	(231)
Income from Continuing Operations Before Income Taxes	697	780	1,333	2,217
Income Tax Benefit (Expense)	263	(131)	46	(570)
Income from Continuing Operations	960	649	1,379	1,647
Income (Loss) from Discontinued Operations, Net of Tax	1	(3)	3	(117)
Net Income	961	646	1,382	1,530
Net Income Attributable to Noncontrolling Interests	(58)	(13)	(169)	(48)
Net Income Attributable to McKesson Corporation	$ 903	$ 633	$ 1,213	$ 1,482
Diluted
Continuing operations (in dollars per share)	$ 4.32	$ 2.86	$ 5.75	$ 7.07
Discontinued operations (in dollars per share)	0.01	(0.01)	0.01	(0.51)
Total (in dollars per share)	4.33	2.85	5.76	6.56
Basic
Continuing operations (in dollars per share)	4.34	2.89	5.78	7.14
Discontinued operations (in dollars per share)	0.01	(0.02)	0.02	(0.52)
Total (in dollars per share)	4.35	2.87	5.80	6.62
Dividends declared per common share (in dollars per share)	$ 0.34	$ 0.28	$ 0.96	$ 0.84
Weighted Average Common Shares
Diluted (in shares)	208	222	210	226
Basic (in shares)	207	221	209	224