| Document and Entity Information | Mar. 04, 2020 |
| Document And Entity Information [Line Items] | |
| Entity Registrant Name | AIR PRODUCTS & CHEMICALS INC /DE/ |
| Amendment Flag | false |
| Entity Central Index Key | 0000002969 |
| Document Type | 8-K |
| Document Period End Date | Mar. 4, 2020 |
| Entity Incorporation State Country Code | DE |
| Entity File Number | 001-04534 |
| Entity Tax Identification Number | 23-1274455 |
| Entity Address, Address Line One | 7201 Hamilton Boulevard |
| Entity Address, City or Town | Allentown |
| Entity Address, State or Province | PA |
| Entity Address, Postal Zip Code | 18195-1501 |
| City Area Code | (610) |
| Local Phone Number | 481-4911 |
| Written Communications | false |
| Soliciting Material | false |
| Pre Commencement Tender Offer | false |
| Pre Commencement Issuer Tender Offer | false |
| Entity Emerging Growth Company | false |
| Common Class A [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | Common Stock, par value $1.00 per share |
| Trading Symbol | APD |
| Security Exchange Name | NYSE |
| Euro Notes Due 2020 Two Percent [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | 2.000% Euro Notes due 2020 |
| Trading Symbol | APD 20 |
| Security Exchange Name | NYSE |
| Euro Notes Due 2021 Point Three Seven Five Percent [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | 0.375% Euro Notes due 2021 |
| Trading Symbol | APD 21B |
| Security Exchange Name | NYSE |
| Euro Notes Due 2025 One Percent [Member] | |
| Document And Entity Information [Line Items] | |
| Security 12b Title | 1.000% Euro Notes due 2025 |
| Trading Symbol | APD 25 |
| Security Exchange Name | NYSE |
