v3.22.0.1

Pension and Other Postretirement Benefits - Plan Asset Allocations (Details) - Pension benefits​ | Dec. 31, 2021 | Dec. 31, 2020
--- | --- | ---
Defined Benefit Plan Disclosure [Line Items] |  |
Plan asset, weighted average asset allocations | 100.00% | 100.00%
Equities |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Plan asset, weighted average asset allocations | 31.00% | 20.00%
Equities | Maximum |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Policy maximum | 40.00% |
Fixed income |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Plan asset, weighted average asset allocations | 56.00% | 51.00%
Fixed income | Maximum |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Policy maximum | 100.00% |
Other investments |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Plan asset, weighted average asset allocations | 13.00% | 29.00%
Other investments | Maximum |  |
Defined Benefit Plan Disclosure [Line Items] |  |
Policy maximum | 30.00% |

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