Goodwill and Intangible Assets, Net - Schedule of Changes in the Carrying Amount of Goodwill (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Dec. 31, 2020	Sep. 30, 2020	Dec. 31, 2019	Dec. 31, 2020	Dec. 31, 2019
Goodwill [Roll Forward]
Beginning balance				$ 9,360
Goodwill acquired				4
Acquisition accounting, transfers and other adjustments				2
Disposals				(1)
Goodwill impairment charges	$ 0		$ (2)	(69)	$ (2)
Foreign currency translation adjustments, net				215
Ending balance	9,511			9,511
U.S. Pharmaceutical
Goodwill [Roll Forward]
Beginning balance				3,924
Goodwill acquired				0
Acquisition accounting, transfers and other adjustments				0
Disposals				(1)
Goodwill impairment charges				0
Foreign currency translation adjustments, net				67
Ending balance	3,990			3,990
International
Goodwill [Roll Forward]
Beginning balance				1,443
Goodwill acquired				4
Acquisition accounting, transfers and other adjustments				0
Disposals				0
Goodwill impairment charges		$ (69)		(69)
Foreign currency translation adjustments, net				148
Ending balance	1,526			1,526
Medical-Surgical Solutions
Goodwill [Roll Forward]
Beginning balance				2,453
Goodwill acquired				0
Acquisition accounting, transfers and other adjustments				0
Disposals				0
Goodwill impairment charges				0
Foreign currency translation adjustments, net				0
Ending balance	2,453			2,453
Prescription Technology Solutions
Goodwill [Roll Forward]
Beginning balance				1,540
Goodwill acquired				0
Acquisition accounting, transfers and other adjustments				2
Disposals				0
Goodwill impairment charges				0
Foreign currency translation adjustments, net				0
Ending balance	$ 1,542			$ 1,542