Segments of Business - Schedule Of Segment Information (Details) - USD ($) $ in Millions	3 Months Ended								12 Months Ended
	Mar. 31, 2020	Dec. 31, 2019	Sep. 30, 2019	Jun. 30, 2019	Mar. 31, 2019	Dec. 31, 2018	Sep. 30, 2018	Jun. 30, 2018	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Revenues
Revenues	$ 58,535	$ 59,172	$ 57,616	$ 55,728	$ 52,429	$ 56,208	$ 53,075	$ 52,607	$ 231,051	$ 214,319	$ 208,357
Operating profit
Operating income									2,410	1,568	1,208
Corporate Expenses, Net									(1,017)	(694)	(564)
Loss on Debt Extinguishment									0	0	(122)
Interest Expense									(249)	(264)	(283)
Income from Continuing Operations Before Income Taxes									1,144	610	239
Depreciation and amortization
Total									922	949	951
Expenditures for long-lived assets
Total									362	426	405
United States
Revenues
Revenues									192,709	176,296	169,943
Foreign
Revenues
Revenues									38,342	38,023	38,414
Operating Segments
Revenues
Revenues									231,051	214,319	208,357
Corporate
Depreciation and amortization
Total									136	122	111
Expenditures for long-lived assets
Total									76	75	99
U.S. Pharmaceutical and Specialty Solutions | Operating Segments
Revenues
Revenues									183,341	167,763	162,587
Operating profit
Operating income									2,767	2,697	2,535
Depreciation and amortization
Total									228	238	210
Expenditures for long-lived assets
Total									94	88	126
European Pharmaceutical Solutions | Operating Segments
Revenues
Revenues									27,390	27,242	27,320
Operating profit
Operating income									(261)	(1,978)	(1,681)
Depreciation and amortization
Total									235	257	296
Expenditures for long-lived assets
Total									95	85	104
Medical-Surgical Solutions | Operating Segments
Revenues
Revenues									8,305	7,618	6,611
Operating profit
Operating income									499	455	461
Depreciation and amortization
Total									136	118	97
Expenditures for long-lived assets
Total									36	110	34
Other | Operating Segments
Revenues
Revenues									12,015	11,696	11,839
Operating profit
Operating income									(595)	394	(107)
Depreciation and amortization
Total									187	214	237
Expenditures for long-lived assets
Total									$ 61	$ 68	$ 42