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v3.23.1

Pension and Postretirement Plans (Narrative) (Details) - Defined Benefit Pension Plan [Member] $ in Thousands | 3 Months Ended | 12 Months Ended
--- | --- | ---
Mar. 31, 2023 USD ($) investment company | Mar. 31, 2022 USD ($) | Dec. 31, 2022 USD ($) investment
Defined Benefit Plan Disclosure [Line Items] |  |  |
Special separation benefit expense | $ 4,129 | $ 0 |
Percent of plan assets managed internally by the company | 41.00% |  |
Percent of plan assets managed by investment companies | 59.00% |  |
Number of investment companies actively managing plan assets | company | 2 |  |
Percentage of total plan assets | 100.00% |  | 100.00%
Berkshire Hathaway Common Stock [Member] | Investment Manager 2 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined benefit plan, target allocation maximum percentage of assets, singular equity security, without prior approval by plan administrator | 20.00% |  |
Alphabet and Berkshire Hathaway Common Stock [Member] | Investment Manager 1 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined benefit plan, target allocation maximum percentage of assets, singular equity security, without prior approval by plan administrator | 15.00% |  |
Foreign Investments [Member] | Maximum [Member] | Investment Manager 1 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined benefit plan, target allocation percentage of assets | 30.00% |  |
Foreign Investments [Member] | Maximum [Member] | Investment Manager 2 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined benefit plan, target allocation percentage of assets | 15.00% |  |
Fixed income securities [Member] | Minimum [Member] | Investment Manager 2 [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined benefit plan, target allocation percentage of assets | 10.00% |  |
Private investment fund [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Percentage of total plan assets | 17.00% |  | 16.00%
Single Equity Concentration [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Defined benefit plan, target allocation maximum percentage of assets, singular equity security, without prior approval by plan administrator | 10.00% |  | 10.00%
Value of investments | $ 876,600 |  | $ 842,600
Percentage of total plan assets | 33.00% |  | 33.00%
Single Equity Concentration [Member] | Equity Securities [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Number of investments the company's pension plan held which individually exceed 10% of total plan assets | investment | 1 |  | 1
Single Equity Concentration [Member] | Private investment fund [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Number of investments the company's pension plan held which individually exceed 10% of total plan assets | investment | 1 |  | 1
Concentration In Single Entity, Type Of Industry, Foreign Country Or Individual Fund [Member] | Defined Benefit Plan Assets Total [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Minimum percentage of plan assets considered as significant concentrations in pension plans | 10.00% |  |
Leaf Group and Code3 [Member] | Separation Incentive Program [Member] |  |  |
Defined Benefit Plan Disclosure [Line Items] |  |  |
Special separation benefit expense | $ 4,100 |  |

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