Quarterly Financial Information (Schedule Of Quarterly Financial Information) (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended																12 Months Ended
	Mar. 31, 2012		Dec. 31, 2011		Sep. 30, 2011		Jun. 30, 2011		Mar. 31, 2011		Dec. 31, 2010		Sep. 30, 2010		Jun. 30, 2010		Mar. 31, 2012		Mar. 31, 2011		Mar. 31, 2010
Quarterly Financial Information [Line Items]
Revenues	$ 31,699		$ 30,839		$ 30,216		$ 29,980		$ 28,853		$ 28,247		$ 27,534		$ 27,450		$ 122,734		$ 112,084		$ 108,702
Gross Profit	1,845		1,566		1,647		1,509		1,751		1,461		1,366		1,392		6,567		5,970		5,676
Net Income	521	[1],[2]	300	[1],[2]	296	[1],[2]	286	[1],[2]	422	[1],[3],[4],[5]	155	[1],[3],[4],[5]	327	[1],[3],[4],[5]	298	[1],[3],[4],[5]	1,403		1,202		1,263
Continuing operations									$ 1.62	[1],[3],[4],[5],[6]	$ 0.60	[1],[3],[4],[5],[6]	$ 0.97	[1],[3],[4],[5],[6]	$ 1.10	[1],[3],[4],[5],[6]	$ 5.59	[6]	$ 4.29	[6]	$ 4.62	[6]
Discontinued operation - gain on sale									$ 0.00	[5]	$ 0.00	[5]	$ 0.28	[5]	$ 0.00	[5]	$ 0.00	[6]	$ 0.28	[6]	$ 0.00	[6]
Total	$ 2.09	[1],[2],[6]	$ 1.20	[1],[2],[6]	$ 1.18	[1],[2],[6]	$ 1.13	[1],[2],[6]	$ 1.62	[1],[3],[4],[5],[6]	$ 0.60	[1],[3],[4],[5],[6]	$ 1.25	[1],[3],[4],[5],[6]	$ 1.10	[1],[3],[4],[5],[6]	$ 5.59	[6]	$ 4.57	[6]	$ 4.62	[6]
Continuing operations									$ 1.65	[1],[3],[4],[5],[6]	$ 0.61	[1],[3],[4],[5],[6]	$ 0.99	[1],[3],[4],[5],[6]	$ 1.12	[1],[3],[4],[5],[6]	$ 5.70	[6]	$ 4.37	[6]	$ 4.70	[6]
Discontinued operation - gain on sale									$ 0.00	[5]	$ 0.00	[5]	$ 0.28	[5]	$ 0.00	[5]	$ 0.00	[6]	$ 0.28	[6]	$ 0.00	[6]
Total	$ 2.14	[1],[2],[6]	$ 1.22	[1],[2],[6]	$ 1.20	[1],[2],[6]	$ 1.15	[1],[2],[6]	$ 1.65	[1],[3],[4],[5],[6]	$ 0.61	[1],[3],[4],[5],[6]	$ 1.27	[1],[3],[4],[5],[6]	$ 1.12	[1],[3],[4],[5],[6]	$ 5.70	[6]	$ 4.65	[6]	$ 4.70	[6]
Gain (Loss) Related to Litigation Settlement																	(149)		(213)		20
Asset impairment charge - capitalized software held for sale																	0		72		0
Discontinued operation - gain on sale, net of tax																	0		72		0
Distribution Solutions [Member]
Quarterly Financial Information [Line Items]
Revenues																	119,424	[7]	108,889	[7]	105,578	[7]
Technology Solutions [Member]
Quarterly Financial Information [Line Items]
Revenues																	3,310		3,195		3,124
Asset impairment charge - capitalized software held for sale													72						72
Pre-tax gain from divestiture													95						95
Discontinued operation - gain on sale, net of tax													72						72
Product alignment charge	9		42														51
Antitrust Class Action Lawsuit [Member] | Distribution Solutions [Member]
Quarterly Financial Information [Line Items]
Share of a settlement of an antitrust class action lawsuit															51				51
Average Wholesale Price Litigation [Member]
Quarterly Financial Information [Line Items]
Litigation charges	4		27		118						189		24				149		213		0
Litigation charges after tax	(32)		15		77						133		16
Average Wholesale Price Litigation [Member] | Distribution Solutions [Member]
Quarterly Financial Information [Line Items]
Litigation charges																	$ 149		$ 213

[1] Financial results for the second, third and fourth quarters of 2012 include AWP litigation charges of $118 million pre-tax ($77 million after-tax), $27 million pre-tax ($15 million after-tax) and $4 million pre-tax (benefit of $32 million after-tax), which were recorded in operating expenses. Financial results for the second and third quarters of 2011 include AWP litigation charges of $24 million pre-tax ($16 million after-tax) and $189 million pre-tax ($133 million after-tax), which were recorded in operating expenses.

[2] Financial results for the third and fourth quarters of 2012 include product alignment charges of $42 million and $9 million.

[3] Financial results for the first quarter of 2011 include the receipt of $51 million representing our share of a settlement of an antitrust class action lawsuit brought against a drug manufacturer, which was recorded as a reduction to cost of sales.

[4] Financial results for the second quarter of 2011 include a $72 million asset impairment charge for capitalized software held for sale, which was recorded to cost of sales.

[5] Financial results for the second quarter of 2011 include a $95 million pre-tax ($72 million after-tax) gain from the sale of MAP.

[6] Certain computations may reflect rounding adjustments.

[7] Revenues derived from services represent less than 2% of this segment's total revenues for 2012, 2011 and 2010.