CONSOLIDATED STATEMENTS OF COMPREHENSIVE INCOME - USD ($) $ in Millions	12 Months Ended
Mar. 31, 2020	Mar. 31, 2019	Mar. 31, 2018
Statement of Comprehensive Income [Abstract]
Net Income	$ 1,120	$ 255	$ 297
Other Comprehensive Income (Loss), Net of Tax
Foreign currency translation adjustments	(66)	(190)	624
Unrealized gains (losses) on cash flow hedges	86	24	(30)
Changes in retirement-related benefit plans	129	(32)	15
Other Comprehensive Income (Loss), Net of Tax	149	(198)	609
Comprehensive Income	1,269	57	906
Comprehensive Income Attributable to Noncontrolling Interests	(223)	(155)	(415)
Comprehensive Income (Loss) Attributable to McKesson Corporation	$ 1,046	$ (98)	$ 491

Amount after tax of increase (decrease) in equity from transactions and other events and circumstances from net income and other comprehensive income, attributable to parent entity. Excludes changes in equity resulting from investments by owners and distributions to owners.

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Amount after tax and reclassification adjustments of gain (loss) on foreign currency translation adjustments, foreign currency transactions designated and effective as economic hedges of a net investment in a foreign entity and intra-entity foreign currency transactions that are of a long-term-investment nature.

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