Segment Information (Schedule Of Segment Information) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended				9 Months Ended
	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2012		Dec. 31, 2011
Segment Reporting Information [Line Items]
Segment Reporting Revenue From External Customers	$ 31,187		$ 30,839		$ 91,835		$ 91,035
Interest Expense	(59)		(64)		(170)		(192)
Income Before Income Taxes	436		426		1,533		1,262
Distribution Solutions [Member]
Segment Reporting Information [Line Items]
Segment Reporting Revenue From External Customers	30,361	[1]	30,016	[1]	89,347	[1]	88,585	[1]
Operating profit	525	[2],[3]	510	[4]	1,646	[2],[3],[4]	1,462	[4]
Distribution Solutions - Direct Distribution And Services [Member]
Segment Reporting Information [Line Items]
Segment Reporting Revenue From External Customers	22,386		21,585		64,625		63,484
Distribution Solutions - Sales To Customers' Warehouses [Member]
Segment Reporting Information [Line Items]
Segment Reporting Revenue From External Customers	4,468		5,198		14,621		14,998
Distribution Solutions - Domestic Pharmaceutical Distribution And Services [Member]
Segment Reporting Information [Line Items]
Segment Reporting Revenue From External Customers	26,854		26,783		79,246		78,482
Distribution Solutions - Canada Pharmaceutical Distribution And Services [Member]
Segment Reporting Information [Line Items]
Segment Reporting Revenue From External Customers	2,633		2,473		7,559		7,739
Distribution Solutions - Medical Surgical Distribution And Services [Member]
Segment Reporting Information [Line Items]
Segment Reporting Revenue From External Customers	874		760		2,542		2,364
Technology Solutions [Member]
Segment Reporting Information [Line Items]
Segment Reporting Revenue From External Customers	826		823		2,488		2,450
Operating profit	79		69	[5]	269		277	[5]
Technology Solutions - Services [Member]
Segment Reporting Information [Line Items]
Segment Reporting Revenue From External Customers	661		643		1,983		1,916
Technology Solutions - Software And Software Systems [Member]
Segment Reporting Information [Line Items]
Segment Reporting Revenue From External Customers	145		152		432		449
Technology Solutions - Hardware [Member]
Segment Reporting Information [Line Items]
Segment Reporting Revenue From External Customers	20		28		73		85
Total of Reportable Segments [Member]
Segment Reporting Information [Line Items]
Operating profit	604		579		1,915		1,739
Corporate [Member]
Segment Reporting Information [Line Items]
Operating profit	$ (109)		$ (89)		$ (212)	[6]	$ (285)

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

[2] Operating profit for the third quarter and first nine months of 2013 includes the receipt of $8 million and $27 million representing our share of settlements of antitrust class action lawsuits brought against drug manufacturers, which were recorded as a reduction to cost of sales.

[3] Operating profit for the third quarter and first nine months of 2013 include a $40 million charge for a legal dispute in our Canadian business, which was recorded in operating expenses.

[4] For the third quarter of 2012, operating profit includes an AWP litigation charge of $27 million. For the first nine months of 2013 and 2012, operating profit includes AWP litigation charges of $60 million and $145 million. These charges were recorded in operating expenses.

[5] Operating profit for the third quarter and first nine months of 2012 includes product alignment charges of $42 million, of which $26 million was recorded in cost of sales and $16 million was recorded in operating expenses.

[6] Corporate expenses for the first nine months of 2013 are net of an $81 million pre-tax gain on business combination related to the acquisition of the remaining 50% ownership interest in our corporate headquarters building.