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Employee Benefit Plans - Weighted Average Asset Allocations by Asset Category (Detail) | Dec. 31, 2019 | Dec. 31, 2018
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Schedule of Defined Benefit Plan Asset Allocation Targets [Line Items] |  |
Actual Asset Allocation as of December 31 (percentage) | 100.00% | 100.00%
Target Asset (percentage) | 100.00% |
Equity securities |  |
Schedule of Defined Benefit Plan Asset Allocation Targets [Line Items] |  |
Actual Asset Allocation as of December 31 (percentage) | 34.00% | 32.00%
Target Asset (percentage) | 32.00% |
Debt securities |  |
Schedule of Defined Benefit Plan Asset Allocation Targets [Line Items] |  |
Actual Asset Allocation as of December 31 (percentage) | 43.00% | 51.00%
Target Asset (percentage) | 49.00% |
Insurance (annuity) contracts |  |
Schedule of Defined Benefit Plan Asset Allocation Targets [Line Items] |  |
Actual Asset Allocation as of December 31 (percentage) | 12.00% | 12.00%
Target Asset (percentage) | 12.00% |
Real estate |  |
Schedule of Defined Benefit Plan Asset Allocation Targets [Line Items] |  |
Actual Asset Allocation as of December 31 (percentage) | 10.00% | 3.00%
Target Asset (percentage) | 4.00% |
Other |  |
Schedule of Defined Benefit Plan Asset Allocation Targets [Line Items] |  |
Actual Asset Allocation as of December 31 (percentage) | 1.00% | 2.00%
Target Asset (percentage) | 3.00% |

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