XML 48 R39.htm IDEA: XBRL DOCUMENT
v3.21.1

Leases (Tables) | 3 Months Ended
--- | ---
Mar. 31, 2021
Leases [Abstract] |
Schedule of Supplemental Balance Sheet Information Related to Leases | Operating lease right-of-use assets and lease liabilities in the Consolidated Balance Sheet were as follows:
| March 31, 2021 |  | December 31, 2020 |  |
Right-of-use assets classified in Other noncurrent assets | $ | 125 |  |  | $ | 131 |  |  |
Current portion of lease liabilities classified in Other current liabilities | 37 |  |  | 38 |  |  |
Long-term portion of lease liabilities classified in Other noncurrent liabilities | 94 |  |  | 100 |  |  |
Total lease liabilities | $ | 131 |  |  | $ | 138 |  |  |

X
- Definition Assets And Liabilities, Lessee [Table Text Block] + References No definition available. + Details
Name: | hwm_AssetsAndLiabilitiesLesseeTableTextBlock
Namespace Prefix: | hwm_
Data Type: | nonnum:textBlockItemType
Balance Type: | na
Period Type: | duration

X
- References No definition available. + Details
Name: | us-gaap_LeasesAbstract
Namespace Prefix: | us-gaap_
Data Type: | xbrli:stringItemType
Balance Type: | na
Period Type: | duration