Business Acquisitions and Divestitures - Fair Values Recognized of Assets Acquired and Liabilities Assumed (Details) - USD ($) $ in Millions	2 Months Ended	12 Months Ended
	May 31, 2019	Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Amounts Recognized
Goodwill		$ 9,360	$ 9,358	$ 10,924
FY20 Measurement Period Adjustments
Goodwill		$ 12	35
Medical Specialties Distributors LLC (“MSD”)
Amounts Recognized
Receivables	$ 112		113
Other current assets, net of cash and cash equivalents acquired	71		72
Goodwill	388		381
Intangible assets	326		326
Other long-term assets	56		55
Current liabilities	(72)		(72)
Other long-term liabilities	(97)		(91)
Net assets acquired, net of cash and cash equivalents	784		$ 784
FY20 Measurement Period Adjustments
Receivables	(1)
Other current assets, net of cash and cash equivalents acquired	(1)
Goodwill	7
Intangible assets	0
Other long-term assets	1
Current liabilities	0
Other long-term liabilities	(6)
Net assets acquired, net of cash and cash equivalents	$ 0