Retirement plans - Schedule of Allocation of Plan Assets (Details) - Retirement Plans |
Dec. 31, 2022 |
Dec. 31, 2021 |
|---|---|---|
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||
| Target Allocation | 100.00% | |
| Allocation of Plan Assets | 100.00% | 100.00% |
| Equity securities | ||
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||
| Target Allocation | 14.00% | |
| Allocation of Plan Assets | 14.00% | 10.00% |
| Debt securities | ||
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||
| Target Allocation | 86.00% | |
| Allocation of Plan Assets | 86.00% | 86.00% |
| Other (including hedge funds and private real estate) | ||
| Defined Benefit Plans and Other Postretirement Benefit Plans Table Text Block [Line Items] | ||
| Target Allocation | 0.00% | |
| Allocation of Plan Assets | 0.00% | 4.00% |