CONDENSED CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2015	Dec. 31, 2014
Statement of Comprehensive Income [Abstract]
Net Income	$ 647	$ 511	$ 1,866	$ 1,399
Other Comprehensive Income (Loss), Net of Tax
Foreign currency translation adjustments arising during period	(246)	(416)	(142)	(995)
Unrealized gains (losses) on cash flow hedges arising during period	(1)	1	5	(1)
Retirement-related benefit plans	15	(16)	(2)	(8)
Other Comprehensive Income (Loss), Net of Tax	(232)	(431)	(139)	(1,004)
Comprehensive Income (Loss)	415	80	1,727	395
Comprehensive Loss (Income) Attributable to Noncontrolling Interests	18	13	(32)	148
Comprehensive Income (Loss) Attributable to McKesson Corporation	$ 433	$ 93	$ 1,695	$ 543