Consolidated Statements of Stockholders' Equity (USD $) In Millions	Total		Common Stock [Member]	Additional Paid-in Capital [Member]	Other Capital [Member]	Retained Earnings [Member]	Accumulated Other Comprehensive Income (Loss) [Member]	Treasury Stock [Member]	Noncontrolling Interest [Member]	Celesio [Member]
Beginning Balance, Total Equity at Mar. 31, 2012	$ 6,831		$ 4	$ 5,571	$ 4	$ 9,451	$ 5	$ (8,204)	$ 0
Beginning Balance, McKesson Stockholders' Equity, Shares at Mar. 31, 2012			373
Beginning Balance, McKesson Stockholders' Equity, Treasury Stock, Shares at Mar. 31, 2012								(138)
Issuance of shares under employee plans	111		0	166				(55)
Issuance of shares under employee plans, shares			5					0
Share-based compensation	167			167
Tax benefit related to issuance of shares under employee plans	34			34
Conversion of Celesio convertible bonds	0
Other comprehensive income (loss)							(70)
Other Comprehensive Income (Loss), Net of Tax	(70)
Net Income Attributable to McKesson	1,338
Net income (loss) attributable to noncontrolling interests	0
Net Income	1,338
Repurchase of common stock	(1,159)	[1]		162				(1,321)
Stock Repurchased and Retired During Period, Shares			(2)					2
Treasury Stock, Retired, Cost Method, Amount	195		0	(22)		(195)		217
Treasury Stock Acquired, Net of Retirements, Amount	0
Repurchase of common stock, Shares	(13.0)	[1],[2],[3]						(13.0)
Cash dividends declared: $0.96 for 2015, $0.92 for 2014 and $0.80 for 2013 per common share	(192)					(192)
Other	10				10
Ending Balance, Total Equity at Mar. 31, 2013	7,070		4	6,078	14	10,402	(65)	(9,363)	0
Ending Balance, McKesson Stockholders' Equity, Shares at Mar. 31, 2013			376
Ending Balance, McKesson Stockholders' Equity, Treasury Stock, Shares at Mar. 31, 2013								(149)
Issuance of shares under employee plans	47		0	177				(130)
Issuance of shares under employee plans, shares			5					(1)
Share-based compensation	160			160
Tax benefit related to issuance of shares under employee plans	92			92
Noncontrolling interests									1,500
Noncontrolling Interest, Increase from Business Combination	1,500
Conversion of Celesio convertible bonds	313			33					280
Other comprehensive income (loss)							62		21
Other Comprehensive Income (Loss), Net of Tax	83
Net Income Attributable to McKesson	1,263					1,263
Net income (loss) attributable to noncontrolling interests	(5)								(5)
Net Income	1,258
Repurchase of common stock	0			14				(14)
Repurchase of common stock, Shares	0							0
Cash dividends declared: $0.96 for 2015, $0.92 for 2014 and $0.80 for 2013 per common share	(214)					(214)
Other	9			(2)	9	2
Ending Balance, Total Equity at Mar. 31, 2014	10,318		4	6,552	23	11,453	(3)	(9,507)	1,796
Ending Balance, McKesson Stockholders' Equity at Mar. 31, 2014	8,522
Ending Balance, McKesson Stockholders' Equity, Shares at Mar. 31, 2014			381
Ending Balance, McKesson Stockholders' Equity, Treasury Stock, Shares at Mar. 31, 2014	(150)							(150)
Issuance of shares under employee plans	43		0	152				(109)
Issuance of shares under employee plans, shares			3					0
Share-based compensation	165			165
Tax benefit related to issuance of shares under employee plans	105			105
Reclassification from total equity to redeemable noncontrolling interests	(1,500)								(1,500)
Purchase of noncontrolling interest	(62)			(2)					(60)
Conversion of Celesio convertible bonds	0
Other comprehensive income (loss)							(1,710)		(174)
Other Comprehensive Income Loss Net Of Tax Excluding Redeemable Noncontrolling Interest	(1,884)
Other Comprehensive Income (Loss), Net of Tax	(1,989)
Net Income Attributable to McKesson	1,476
Net income (loss) attributable to noncontrolling interests	67								5
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest, Excluding Redeemable Noncontrolling Interest	1,481
Net Income	1,543
Repurchase of common stock	(340)	[1]						(340)
Repurchase of common stock, Shares	(1.5)	[1],[2],[3]						(2.0)
Cash dividends declared: $0.96 for 2015, $0.92 for 2014 and $0.80 for 2013 per common share	(226)					(226)
Other	(15)			(4)	(30)	2			17
Ending Balance, Total Equity at Mar. 31, 2015	8,085		4	6,968	(7)	12,705	(1,713)	(9,956)	84
Ending Balance, McKesson Stockholders' Equity at Mar. 31, 2015	$ 8,001
Ending Balance, McKesson Stockholders' Equity, Shares at Mar. 31, 2015			384
Ending Balance, McKesson Stockholders' Equity, Treasury Stock, Shares at Mar. 31, 2015	(152)							(152)

[1] This table does not include shares tendered to satisfy the exercise price in connection with cashless exercises of employee stock options or shares tendered to satisfy tax withholding obligations in connection with employee equity awards.

[2] All of the shares purchased were part of the publicly announced programs.

[3] The number of shares purchased reflects rounding adjustments.