Cover - USD ($) $ in Billions	12 Months Ended
	Sep. 30, 2021	Oct. 31, 2021	Mar. 31, 2021
Entity Information [Line Items]
Document Type	10-K
Document Annual Report	true
Document Transition Report	false
Document Period End Date	Sep. 30, 2021
Document Fiscal Year Focus	2021
Document Fiscal Period Focus	FY
Current Fiscal Year End Date	--09-30
Entity Central Index Key	0000002969
Amendment Flag	false
Entity File Number	001-04534
Entity Registrant Name	AIR PRODUCTS AND CHEMICALS, INC.
Entity Incorporation, State or Country Code	DE
Entity Tax Identification Number	23-1274455
Entity Address, Address Line One	1940 Air Products Boulevard
Entity Address, City or Town	Allentown
Entity Address, State or Province	PA
Entity Address, Postal Zip Code	18106-5500
City Area Code	610
Local Phone Number	481-4911
Entity Well-known Seasoned Issuer	Yes
Entity Voluntary Filers	No
Entity Current Reporting Status	Yes
Entity Interactive Data Current	Yes
Entity Filer Category	Large Accelerated Filer
Entity Small Business	false
Entity Emerging Growth Company	false
ICFR Auditor Attestation Flag	true
Entity Shell Company	false
Entity Public Float			$ 62.1
Entity Common Stock, Shares Outstanding		221,460,382
Documents Incorporated by Reference	Portions of the registrant’s definitive Proxy Statement for the Annual Meeting of Shareholders to be held on 3 February 2022 are incorporated by reference into Part III.
Common Stock, par value, $1.00 per share
Entity Information [Line Items]
Title of 12(b) Security	Common Stock, par value $1.00 per share
Trading Symbol	APD
Security Exchange Name	NYSE
1.000% Euro Notes due 2025
Entity Information [Line Items]
Title of 12(b) Security	1.000% Euro Notes due 2025
Trading Symbol	APD25
Security Exchange Name	NYSE
0.500% Notes due 2028
Entity Information [Line Items]
Title of 12(b) Security	0.500% Euro Notes due 2028
Trading Symbol	APD28
Security Exchange Name	NYSE
0.800% Notes due 2032
Entity Information [Line Items]
Title of 12(b) Security	0.800% Euro Notes due 2032
Trading Symbol	APD32
Security Exchange Name	NYSE