Condensed Consolidated Statements Of Operations (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended				9 Months Ended
	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2014		Dec. 31, 2013
Income Statement [Abstract]
Revenues	$ 47,005		$ 34,336		$ 135,821		$ 99,560
Cost of Sales	(44,063)		(32,486)		(127,159)		(93,759)
Gross Profit	2,942		1,850		8,662		5,801
Operating Expenses	(2,162)		(1,339)		(6,406)		(3,899)
Litigation Charges	0		(18)		0		(68)
Total Operating Expenses	(2,162)		(1,357)		(6,406)		(3,967)
Operating Income	780		493		2,256		1,834
Other Income (Loss), Net	13		(6)		57		9
Interest Expense	(97)		(69)		(297)		(187)
Income from Continuing Operations Before Income Taxes	696		418		2,016		1,656
Income Tax Expense	(183)		(254)		(587)		(641)
Income from Continuing Operations	513		164		1,429		1,015
Loss from discontinued operations, net of tax	(2)		(99)		(30)		(122)
Net Income	511		65		1,399		893
Net Income Attributable to Noncontrolling Interests	(39)		0		(55)		0
Net income attributable to McKesson	$ 472		$ 65		$ 1,344		$ 893
Earnings (Loss) Per Common Share Attributable To McKesson (Diluted)
Continuing operations	$ 2.01	[1]	$ 0.70	[1]	$ 5.84	[1]	$ 4.36	[1]
Discontinued operations	$ (0.01)	[1]	$ (0.42)	[1]	$ (0.12)	[1]	$ (0.53)	[1]
Total	$ 2.00	[1]	$ 0.28	[1]	$ 5.72	[1]	$ 3.83	[1]
Earnings (Loss) Per Common Share Attributable To McKesson (Basic)
Continuing operations	$ 2.04	[1]	$ 0.71	[1]	$ 5.93	[1]	$ 4.43	[1]
Discontinued operations	$ (0.01)	[1]	$ (0.43)	[1]	$ (0.13)	[1]	$ (0.53)	[1]
Total	$ 2.03	[1]	$ 0.28	[1]	$ 5.80	[1]	$ 3.90	[1]
Dividends Declared Per Common Share	$ 0.24		$ 0.24		$ 0.72		$ 0.68
Weighted Average Common Shares
Diluted	236		234		235		233
Basic	232		230		232		229

[1] Certain computations may reflect rounding adjustments.