Segment Information (Details) $ in Millions	3 Months Ended
	Jun. 30, 2017 USD ($) segment	Mar. 31, 2017 USD ($)	Jun. 30, 2016 USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment	2
Revenues
Total Revenues	$ 51,051		$ 49,733
Operating profit
Total	633		972
Interest Expense	(68)		(79)
Income from Continuing Operations Before Income Taxes	458		912
Loss from equity method investment in Change Healthcare	120		0
Gain from sale of business, pre-tax	37		0
Operating Segments
Revenues
Total Revenues	51,051		49,733
Operating profit
Total	635		1,096
Operating Segments | Total Distribution Solutions
Revenues
Total Revenues	50,931		49,009
Operating profit
Total	$ 713		$ 928
Revenue derived from services, percentage (less than)	2.00%		2.00%
Proceeds from legal settlements			$ 142
Operating Segments | Total Distribution Solutions | LIFO Method of Accounting
Operating profit
Total	$ 26		47
Operating Segments | Total Distribution Solutions | Reportable Subsegments | North America pharmaceutical distribution and services
Revenues
Total Revenues	43,016		41,211
Operating Segments | Total Distribution Solutions | Reportable Subsegments | International pharmaceutical distribution and services
Revenues
Total Revenues	6,382		6,330
Operating Segments | Total Distribution Solutions | Reportable Subsegments | Medical-Surgical distribution and services
Revenues
Total Revenues	1,533		1,468
Operating Segments | Technology Solutions
Revenues
Total Revenues	120		724
Operating profit
Total	(78)		168
Corporate
Operating profit
Corporate Expenses, Net	(109)		(105)
Segment Reconciling Items
Operating profit
Interest Expense	(68)		$ (79)
Joint Venture | Change Healthcare, LLC (“Change Healthcare”)
Operating profit
Loss from equity method investment in Change Healthcare	120
Core MTS Businesses | Change Healthcare, LLC (“Change Healthcare”) | Operating Segments | Technology Solutions
Operating profit
Gain from sale of business, pre-tax	$ 37	$ 3,947