CONDENSED CONSOLIDATED STATEMENTS OF OPERATIONS - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Income Statement [Abstract]
Total Revenues	$ 52,607	$ 51,051
Cost of Sales	49,828	48,491
Gross Profit	2,779	2,560
Operating Expenses	(2,127)	(1,927)
Goodwill Impairment Charges	(570)	0
Restructuring and Asset Impairment Charges	(96)	0
Gain from Escrow Settlement	97	0
Total Operating Expenses	(2,696)	(1,927)
Operating Income	83	633
Other Income, Net	40	13
Loss from Equity Method Investment in Change Healthcare	(56)	(120)
Interest Expense	(61)	(68)
Income from Continuing Operations Before Income Taxes	6	458
Income Tax Expense	(87)	(95)
Income (Loss) from Continuing Operations	(81)	363
Income from Discontinued Operations, Net of Tax	1	2
Net Income (Loss)	(80)	365
Net Income Attributable to Noncontrolling Interests	(58)	(56)
Net Income (Loss) Attributable to McKesson Corporation	$ (138)	$ 309
Diluted
Continuing operations (in dollars per share)	$ (0.69)	$ 1.44
Discontinued operations (in dollars per share)	0.01	0.01
Total (in dollars per share)	(0.68)	1.45
Basic
Continuing operations (in dollars per share)	(0.69)	1.46
Discontinued operations (in dollars per share)	0.01	0.00
Total (in dollars per share)	(0.68)	1.46
Dividends declared per common share (in dollars per share)	$ 0.34	$ 0.28
Weighted Average Common Shares
Diluted (in shares)	202	213
Basic (in shares)	202	211