Goodwill and Intangible Assets, Net - Schedule of Changes in the Carrying Amount of Goodwill and Narrative (Details) - USD ($) $ in Millions	3 Months Ended			9 Months Ended
	Dec. 31, 2018	Jun. 30, 2018	Dec. 31, 2017	Dec. 31, 2018	Dec. 31, 2017
Goodwill [Roll Forward]
Beginning balance		$ 10,924		$ 10,924
Goodwill acquired				424
Goodwill impairment charges	$ (21)		$ 0	(591)	$ (350)
Acquisition accounting, transfers and other adjustments				31
Foreign currency translation adjustments, net				(269)
Ending balance	10,519			10,519
U.S. Pharmaceutical and Specialty Solutions
Goodwill [Roll Forward]
Beginning balance		4,110		4,110
Goodwill acquired				0
Goodwill impairment charges				0
Acquisition accounting, transfers and other adjustments				13
Foreign currency translation adjustments, net				(49)
Ending balance	4,074			4,074
European Pharmaceutical Solutions
Goodwill [Roll Forward]
Beginning balance		1,850		1,850
Goodwill acquired				52
Goodwill impairment charges		(570)		(570)
Acquisition accounting, transfers and other adjustments				(4)
Foreign currency translation adjustments, net				(135)
Ending balance	1,193			1,193
Medical-Surgical Solutions
Goodwill [Roll Forward]
Beginning balance		2,070		2,070
Goodwill acquired				360
Goodwill impairment charges				0
Acquisition accounting, transfers and other adjustments				16
Foreign currency translation adjustments, net				0
Ending balance	2,446			2,446
Other
Goodwill [Roll Forward]
Beginning balance		$ 2,894		2,894
Goodwill acquired				12
Goodwill impairment charges				(21)
Acquisition accounting, transfers and other adjustments				6
Foreign currency translation adjustments, net				(85)
Ending balance	$ 2,806			$ 2,806