Goodwill and Intangible Assets, Net - Schedule of Changes in the Carrying Amount of Goodwill and Narrative (Details) - USD ($) $ in Millions	3 Months Ended
	Jun. 30, 2018	Jun. 30, 2017
Goodwill [Roll Forward]
Beginning balance	$ 10,924
Goodwill acquired	391
Goodwill impairment charges	(570)	$ 0
Acquisition accounting, transfers and other adjustments	10
Foreign currency translation adjustments, net	(170)
Ending balance	10,585
U.S. Pharmaceutical and Specialty Solutions
Goodwill [Roll Forward]
Beginning balance	4,110
Goodwill acquired	0
Goodwill impairment charges	0
Acquisition accounting, transfers and other adjustments	4
Foreign currency translation adjustments, net	(36)
Ending balance	4,078
European Pharmaceutical Solutions
Goodwill [Roll Forward]
Beginning balance	1,850
Goodwill acquired	31
Goodwill impairment charges	(570)
Acquisition accounting, transfers and other adjustments	0
Foreign currency translation adjustments, net	(98)
Ending balance	1,213
Medical-Surgical Solutions
Goodwill [Roll Forward]
Beginning balance	2,070
Goodwill acquired	360
Goodwill impairment charges	0
Acquisition accounting, transfers and other adjustments	0
Foreign currency translation adjustments, net	0
Ending balance	2,430
Other
Goodwill [Roll Forward]
Beginning balance	2,894
Goodwill acquired	0
Goodwill impairment charges	0
Acquisition accounting, transfers and other adjustments	6
Foreign currency translation adjustments, net	(36)
Ending balance	$ 2,864