Segments of Business - Schedule Of Segment Information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2018	Dec. 31, 2017	Sep. 30, 2017	Jun. 30, 2017	Mar. 31, 2019	Mar. 31, 2018	Mar. 31, 2017
Revenues
Revenues	$ 52,429	$ 56,208	$ 53,075	$ 52,607	$ 51,628	$ 53,617	$ 52,061	$ 51,051	$ 214,319	$ 208,357	$ 198,533
Operating profit
Corporate Expenses, Net									(694)	(564)	(377)
Loss on Debt Extinguishment									0	(122)	0
Interest Expense									(264)	(283)	(308)
Income from Continuing Operations Before Income Taxes									610	239	6,891
Depreciation and amortization
Total									949	951	910
Expenditures for long-lived assets
Total									426	405	404
United States
Revenues
Revenues									176,296	169,943	164,428
Foreign
Revenues
Revenues									38,023	38,414	34,105
Operating Segments
Revenues
Revenues									214,319	208,357	198,533
Operating profit
Operating income									1,568	1,208	7,576
Corporate
Depreciation and amortization
Total									122	111	110
Expenditures for long-lived assets
Total									75	99	98
U.S. Pharmaceutical and Specialty Solutions | Operating Segments
Revenues
Revenues									167,763	162,587	155,236
Operating profit
Operating income									2,697	2,535	2,488
Depreciation and amortization
Total									238	210	235
Expenditures for long-lived assets
Total									88	126	109
European Pharmaceutical Solutions | Operating Segments
Revenues
Revenues									27,242	27,320	24,847
Operating profit
Operating income									(1,978)	(1,681)	173
Depreciation and amortization
Total									257	296	315
Expenditures for long-lived assets
Total									85	104	125
Medical-Surgical Solutions | Operating Segments
Revenues
Revenues									7,618	6,611	6,244
Operating profit
Operating income									455	461	401
Depreciation and amortization
Total									118	97	101
Expenditures for long-lived assets
Total									110	34	9
Other | Operating Segments
Revenues
Revenues									11,696	11,839	12,206
Operating profit
Operating income									394	(107)	4,514
Depreciation and amortization
Total									214	237	149
Expenditures for long-lived assets
Total									$ 68	$ 42	$ 63