Commitments and Contingent Liabilities (Details)									1 Months Ended		12 Months Ended
	May 03, 2022 USD ($)	Apr. 27, 2022 USD ($)	Apr. 02, 2022 USD ($) installment	Sep. 28, 2021 USD ($)	Feb. 25, 2019	Apr. 03, 2018 city state	May 17, 2013 USD ($)	Apr. 16, 2013 defendant state relator	Jul. 31, 2020 state	Dec. 31, 2019 complaint relator	Mar. 31, 2022 USD ($) case site product	Dec. 31, 2021 USD ($)	Mar. 31, 2021 USD ($)	Mar. 31, 2020 USD ($)	Feb. 25, 2022 product	Sep. 30, 2021 USD ($)	Oct. 23, 2020 case	Nov. 30, 2019 complaint	Oct. 31, 2019 complaint	Aug. 13, 2019 faxNumber fax	Dec. 12, 2018 officer	Aug. 31, 2018 softwareProduct case
Loss Contingencies [Line Items]
Annual surcharge											$ 100,000,000
U.S. Pharmaceutical | Operating Segments
Loss Contingencies [Line Items]
Net cash proceeds from settlements											$ (46,000,000)		$ (181,000,000)	$ (22,000,000)
New York Opioid Tax Surcharge | U.S. Pharmaceutical
Loss Contingencies [Line Items]
Charge recorded related to Company's share of the litigation settlement													50,000,000
After-tax charge recorded related to Company's share of the litigation settlement													37,000,000
Loss contingency accrual, payments												$ 26,000,000
Environmental Litigation
Loss Contingencies [Line Items]
Number of sites | site											5
Remediation costs											$ 15,000,000
Hazardous substance sites, number | site											14
Number of sites selected for preferred remediation | site											1
Estimated environmental assessment and cleanup costs											$ 1,400,000,000
Estimated loss											29,000,000
National Prescription Opiate Litigation
Loss Contingencies [Line Items]
Loss contingency, accrual, current											1,046,000,000		0
Loss contingency, accrual, noncurrent											7,220,000,000		8,067,000,000
Loss contingency accrual											$ 8,266,000,000		$ 8,067,000,000
Canada | National Prescription Opiate Litigation
Loss Contingencies [Line Items]
Number of complaints served | case											4
Canada | National Prescription Opiate Litigation | Governmental Entities
Loss Contingencies [Line Items]
Number of complaints served | case											3
Canada | National Prescription Opiate Litigation | Individual Claimant
Loss Contingencies [Line Items]
Number of complaints served | case											1
United States ex rel. Manchester v. Purdue Pharma, L.P., et al
Loss Contingencies [Line Items]
Period within which party can be substituted					90 days
United States of America, ex rel. Carl Kelley and Michael McElligott, 19-cv-2233, and State of California, ex rel. Carl Kelley and Michael McElligott, CGC-19-576931
Loss Contingencies [Line Items]
Number of complaints served | complaint										2
Number of relators alleging violations | relator										2
Insurance Coverage Litigation
Loss Contingencies [Line Items]
Number of complaints served | case																	2
True Health Chiropractic Inc., et al. v. McKesson Corporation, et al
Loss Contingencies [Line Items]
Number of faxes remaining in class | faxNumber																				9,490
Number of faxes received | fax																				48,769
True Health Chiropractic Inc., et al. v. McKesson Corporation, et al | Subsequent Event
Loss Contingencies [Line Items]
Loss contingency, statutory damages		$ 6,500
True Health Chiropractic Inc., et al. v. McKesson Corporation, et al | Minimum
Loss Contingencies [Line Items]
Damages sought per violation							$ 500
True Health Chiropractic Inc., et al. v. McKesson Corporation, et al | Maximum
Loss Contingencies [Line Items]
Damages sought per violation							$ 1,500
United States ex rel. Omni Healthcare Inc. v. McKesson Corporation, et al.
Loss Contingencies [Line Items]
Number of cities filed on behalf of | city						2
Number of states filed on behalf of | state						30
Evanston Police Pension Fund v. McKesson Corporation
Loss Contingencies [Line Items]
Number of former officers | officer																					2
Powell Prescription Center, et al. v. Surescripts, LLC, et al., and Intergrated Pharmaceutical Solutions LLC v. Surescripts, LLC
Loss Contingencies [Line Items]
Number of complaints served | complaint																			3
Kennebunk Village Pharmacy, Inc. v. SureScripts, LLC, et al., 1:19-cv-7445; Whitman v. SureScripts, LLC et al., No. 1:19-cv-7448; BBK Global Corp. v. SureScripts, LLC et al., 1:19-cv-7640
Loss Contingencies [Line Items]
Number of complaints served | complaint																		3
United States ex rel. Hart v. McKesson Corporation, et al., 15-cv-00903-RA
Loss Contingencies [Line Items]
Number of states filed on behalf of | state									27
Consolidated Actions v SureScripts, LLC
Loss Contingencies [Line Items]
Number of complaints served | complaint										6
Civil Investigative Demands by the U.S. Attorney’s Office for the Eastern District of New York
Loss Contingencies [Line Items]
Number of complaints served | case																						2
Number of software products | softwareProduct																						2
National Prescription Opiate Litigation
Loss Contingencies [Line Items]
Number of states | product											46
Number of eligible states | product											49
Number of eligible political subdivisions, participation percentage (in percent)											98.00%
National Prescription Opiate Litigation | Cherokee Nation
Loss Contingencies [Line Items]
Aggregate amount expected to be paid				$ 29,000,000
Litigation settlement, amount awarded to other party, percentage of total settlement award				38.10%
Loss contingency, settlement, installment payments, term (in years)				6 years 6 months
National Prescription Opiate Litigation | Native American Tribes Other Than Cherokee Nation
Loss Contingencies [Line Items]
Aggregate amount expected to be paid				$ 167,000,000
Litigation settlement, amount awarded to other party, percentage of total settlement award				38.10%
Loss contingency, settlement, installment payments, term (in years)				6 years
Percentage of total settlement to be used to remediate damages (in percent)				0.85
National Prescription Opiate Litigation | Three National Pharmaceutical Distributors | Cherokee Nation
Loss Contingencies [Line Items]
Aggregate amount expected to be paid				$ 75,000,000
National Prescription Opiate Litigation | Three National Pharmaceutical Distributors | Native American Tribes Other Than Cherokee Nation
Loss Contingencies [Line Items]
Aggregate amount expected to be paid				$ 440,000,000
National Prescription Opiate Litigation | Pending Litigation | Alabama | Subsequent Event
Loss Contingencies [Line Items]
Aggregate amount expected to be paid			$ 141,000,000
Litigation settlement payments			$ 33,000,000
Settlement, payment terms | installment			10
National Prescription Opiate Litigation | Settled Litigation | Settling Governmental Entities
Loss Contingencies [Line Items]
Payments for legal settlements											$ 157,000,000
Escrow deposit											$ 41,000,000					$ 354,000,000
National Prescription Opiate Litigation | Settled Litigation | Settling Governmental Entities | Subsequent Event
Loss Contingencies [Line Items]
Aggregate amount expected to be paid			$ 7,400,000,000
Litigation settlement, amount awarded to other party, percentage of total settlement award			38.10%
National Prescription Opiate Litigation | Settled Litigation | State of Washington and Subdivisions | Subsequent Event
Loss Contingencies [Line Items]
Aggregate amount expected to be paid	$ 197,000,000
Litigation settlement, amount awarded to other party, percentage of total settlement award	38.10%
National Prescription Opiate Litigation | Settled Litigation | Distributors | Settling Governmental Entities
Loss Contingencies [Line Items]
Number of other defendants | product															2
National Prescription Opiate Litigation | Settled Litigation | Distributors | Settling Governmental Entities | Subsequent Event
Loss Contingencies [Line Items]
Aggregate amount expected to be paid			$ 19,500,000,000
Expected payment period			18 years
Litigation settlement, award amount to be used by state and local government			85.00%
National Prescription Opiate Litigation | Settled Litigation | Distributors | State of Washington and Subdivisions | Subsequent Event
Loss Contingencies [Line Items]
Aggregate amount expected to be paid	$ 518,000,000
United States ex rel. Piacentile v. Amgen Inc., et al.
Loss Contingencies [Line Items]
Number of relators | relator								2
Number of additional defendants | defendant								5
Number of states filed on behalf of | state								21