Segment Information (Details) $ in Millions	3 Months Ended				9 Months Ended
	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Dec. 31, 2015 USD ($)	Jun. 30, 2015 USD ($)	Dec. 31, 2016 USD ($) segment	Dec. 31, 2015 USD ($)
Segment Reporting [Abstract]
Number of operating segments | segment					2
Revenues
Total Revenues	$ 50,130		$ 47,899		$ 149,820	$ 144,206
Operating profit
Total	831		920		2,383	2,805
Interest Expense	(74)		(87)		(231)	(267)
Income from Continuing Operations Before Income Taxes	780		846		2,217	2,581
Gain on disposition of business					(113)	103
Goodwill impairment charge	0		0		290	0
Total Distribution Solutions
Operating profit
Goodwill impairment charge					0
Technology Solutions
Operating profit
Goodwill impairment charge		$ 290			290
Operating Segments
Revenues
Total Revenues	50,130		47,899		149,820	144,206
Operating profit
Total	945		1,028		2,718	3,168
Operating Segments | Total Distribution Solutions
Revenues
Total Revenues	49,436		47,205		147,722	142,055
Operating profit
Total	$ 813		$ 906		$ 2,592	$ 2,742
Revenue derived from services, percentage (less than)	2.00%		2.00%		2.00%	2.00%
Proceeds from legal settlements					$ 142	$ 76
Operating Segments | Total Distribution Solutions | ZEE Medical Business
Operating profit
Gain on disposition of business						52
Operating Segments | Total Distribution Solutions | LIFO Method of Accounting
Operating profit
Total	$ 155		$ (33)		151	(215)
Operating Segments | Total Distribution Solutions | Reportable Subsegments | North America pharmaceutical distribution and services
Revenues
Total Revenues	41,685		39,615		124,271	119,750
Operating Segments | Total Distribution Solutions | Reportable Subsegments | International pharmaceutical distribution and services
Revenues
Total Revenues	6,193		6,022		18,794	17,726
Operating Segments | Total Distribution Solutions | Reportable Subsegments | Medical-Surgical distribution and services
Revenues
Total Revenues	1,558		1,568		4,657	4,579
Operating Segments | Technology Solutions
Revenues
Total Revenues	694		694		2,098	2,151
Operating profit
Total	132		122		126	426
Operating Segments | Technology Solutions | Nurse Triage
Operating profit
Gain on disposition of business				$ 51		51
Corporate
Operating profit
Corporate Expenses, Net	(91)		$ (95)		(270)	$ (320)
New Company | Operating Expenses | Technology Solutions
Operating profit
Expenses associated with the formation of the joint venture	$ 31				$ 58