Segment Information (Schedule Of Segment Information) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				6 Months Ended
	Sep. 30, 2012		Sep. 30, 2011		Sep. 30, 2012		Sep. 30, 2011
Segment Reporting Information [Line Items]
Segment Reporting Revenue From External Customers	$ 29,850		$ 30,216		$ 60,648		$ 60,196
Interest Expense	(55)		(64)		(111)		(128)
Income Before Income Taxes	566		420		1,097		836
Distribution Solutions [Member]
Segment Reporting Information [Line Items]
Segment Reporting Revenue From External Customers	29,026	[1]	29,391	[1]	58,986	[1]	58,569	[1]
Operating profit	621	[2]	477	[2]	1,121	[2]	952	[2]
Distribution Solutions - Direct Distribution And Services [Member]
Segment Reporting Information [Line Items]
Segment Reporting Revenue From External Customers	20,938		21,072		42,239		41,899
Distribution Solutions - Sales To Customers' Warehouses [Member]
Segment Reporting Information [Line Items]
Segment Reporting Revenue From External Customers	4,806		4,909		10,153		9,800
Distribution Solutions - Domestic Pharmaceutical Distribution And Services [Member]
Segment Reporting Information [Line Items]
Segment Reporting Revenue From External Customers	25,744		25,981		52,392		51,699
Distribution Solutions - Canada Pharmaceutical Distribution And Services [Member]
Segment Reporting Information [Line Items]
Segment Reporting Revenue From External Customers	2,409		2,537		4,926		5,266
Distribution Solutions - Medical Surgical Distribution And Services [Member]
Segment Reporting Information [Line Items]
Segment Reporting Revenue From External Customers	873		873		1,668		1,604
Technology Solutions [Member]
Segment Reporting Information [Line Items]
Segment Reporting Revenue From External Customers	824		825		1,662		1,627
Operating profit	97		108		190		208
Technology Solutions - Services [Member]
Segment Reporting Information [Line Items]
Segment Reporting Revenue From External Customers	656		643		1,322		1,273
Technology Solutions - Software And Software Systems [Member]
Segment Reporting Information [Line Items]
Segment Reporting Revenue From External Customers	142		153		287		297
Technology Solutions - Hardware [Member]
Segment Reporting Information [Line Items]
Segment Reporting Revenue From External Customers	26		29		53		57
Total of Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating profit	718		585		1,311		1,160
Corporate [Member]
Segment Reporting Information [Line Items]
Operating profit	$ (97)		$ (101)		$ (103)	[3]	$ (196)

[1] Revenues derived from services represent less than 2% of this segment’s total revenues.

[2] perating profit includes AWP litigation charges of $44 million and $118 million, and for the first six months of 2013 and 2012, $60 million and $118 million. These charges were recorded in operating expenses. Operating profit for the second quarter and first six months of 2013 includes the receipt of $19 million representing our share of settlements of antitrust class action lawsuits brought against drug manufacturers, which was recorded as a reduction to cost of sales.

[3] Corporate expenses for the first six months of 2013 are net of an $81 million gain on business combination.