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Pensions and Other Postretirement Plans (Narrative) (Details)	1 Months Ended	3 Months Ended				12 Months Ended
	Dec. 31, 2019 USD ($) retirees_beneficiaries	Jun. 30, 2021 USD ($)	Sep. 30, 2020 USD ($)	Jun. 30, 2020 USD ($)	Jun. 30, 2019 USD ($)	Dec. 31, 2021 USD ($) country multiemployer_plan investment	Dec. 31, 2020 USD ($) multiemployer_plan investment	Dec. 31, 2019 USD ($) multiemployer_plan
Retirement Benefits Disclosure [Line Items]
Special separation benefit expense							$ 13,781,000
Number of multiemployer plans contributed to \| multiemployer_plan						1	1	1
Contributions to multiemployer pension plans						$ 100,000	$ 100,000	$ 100,000
Expense associated with the retirement benefits provided under incentive savings plans						10,900,000	8,800,000	9,800,000
Pension Plans [Member]
Retirement Benefits Disclosure [Line Items]
Settlement						0	0	91,676,000
Special separation benefit expense						1,132,000	13,781,000	6,432,000
Accumulated benefit obligation						1,052,700,000	1,064,300,000
Company contributions						0	0
Estimated employer contributions in next fiscal year						0
Net Periodic Cost (Benefit) for the Year						$ (93,030,000)	$ (55,354,000)	(52,665,000)
Percent of Plan Assets Managed Internally by Company						39.00%
Percent Of Plan Assets Managed By Investment Companies						61.00%
Number of investment companies actively managing plan assets \| country						2
Percentage of total plan assets						100.00%	100.00%
Pension Plans [Member] \| Irrevocable Group Annuity Contract Purchase [Member]
Retirement Benefits Disclosure [Line Items]
Payment for settlement	$ 216,800,000
Settlement of obligation	$ 212,100,000
Number of retirees and beneficiaries \| retirees_beneficiaries	3,800
Settlement	$ 91,700,000
Supplemental Executive Retirement Plan (SERP) [Member]
Retirement Benefits Disclosure [Line Items]
Accumulated benefit obligation						$ 112,200,000	$ 121,700,000
Company contributions						5,918,000	5,974,000
Other Postretirement Plans [Member]
Retirement Benefits Disclosure [Line Items]
Settlement						120,000	0	0
Company contributions						375,000	405,000
Net Periodic Cost (Benefit) for the Year						$ (3,425,000)	$ (4,362,000)	$ (11,434,000)
Discount rate to determine benefit obligation						2.23%	1.78%
Discount rate to determine periodic cost						1.78%	2.68%	3.69%
Other Postretirement Plans [Member] \| Pre-Age 65 [Member]
Retirement Benefits Disclosure [Line Items]
Assumed health care cost trend rate						6.17%
Direction of change for assumed health care cost trend rate						decreasing
Ultimate health care cost trend rate						4.50%
Year that rate reaches ultimate trend rate						2032
Other Postretirement Plans [Member] \| Post-Age 65 [Member]
Retirement Benefits Disclosure [Line Items]
Assumed health care cost trend rate						6.52%
Direction of change for assumed health care cost trend rate						decreasing
Ultimate health care cost trend rate						4.50%
Year that rate reaches ultimate trend rate						2032
Other Postretirement Plans [Member] \| Medicare Advantage [Member]
Retirement Benefits Disclosure [Line Items]
Assumed health care cost trend rate						8.00%
Direction of change for assumed health care cost trend rate						decreasing
Ultimate health care cost trend rate						4.50%
Year that rate reaches ultimate trend rate						2032
Private investment fund [Member] \| Pension Plans [Member]
Retirement Benefits Disclosure [Line Items]
Percentage of total plan assets						17.00%	18.00%
Single Equity Concentration [Member] \| Pension Plans [Member]
Retirement Benefits 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						$ 998,800,000	$ 850,600,000
Percentage of total plan assets						29.00%	30.00%
Single Equity Concentration [Member] \| Equity securities [Member] \| Pension Plans [Member]
Retirement Benefits 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] \| Pension Plans [Member]
Retirement Benefits Disclosure [Line Items]
Number of investments the company's pension plan held which individually exceed 10% of total plan assets \| investment						1	1
Defined Benefit Plan Assets Total [Member] \| Concentration In Single Entity, Type Of Industry, Foreign Country Or Individual Fund [Member] \| Pension Plans [Member]
Retirement Benefits Disclosure [Line Items]
Minimum percentage of plan assets considered as significant concentrations in pension plans						10.00%
Separation Incentive Program [Member] \| Pension Plans [Member] \| Group Dekko [Member]
Retirement Benefits Disclosure [Line Items]
Special separation benefit expense		$ 1,100,000
Education [Member] \| Separation Incentive Program [Member] \| Pension Plans [Member]
Retirement Benefits Disclosure [Line Items]
Special separation benefit expense			$ 7,800,000		$ 6,400,000
Education Code3 And Decile [Member] \| Separation Incentive Program [Member] \| Pension Plans [Member]
Retirement Benefits Disclosure [Line Items]
Special separation benefit expense				$ 6,000,000
Investment Manager 1 [Member] \| Alphabet And Berkshire Hathaway Common Stock [Member] \| Pension Plans [Member]
Retirement Benefits Disclosure [Line Items]
Defined benefit plan, target allocation maximum percentage of assets, singular equity security, without prior approval by plan administrator						15.00%
Investment Manager 1 [Member] \| Maximum [Member] \| Foreign Investments [Member] \| Pension Plans [Member]
Retirement Benefits Disclosure [Line Items]
Defined benefit plan, target allocation percentage of assets						30.00%
Investment Manager 2 [Member] \| Berkshire Hathaway Common Stock [Member] \| Pension Plans [Member]
Retirement Benefits Disclosure [Line Items]
Defined benefit plan, target allocation maximum percentage of assets, singular equity security, without prior approval by plan administrator						20.00%
Investment Manager 2 [Member] \| Maximum [Member] \| Foreign Investments [Member] \| Pension Plans [Member]
Retirement Benefits Disclosure [Line Items]
Defined benefit plan, target allocation percentage of assets						15.00%
Investment Manager 2 [Member] \| Minimum [Member] \| Fixed income securities [Member] \| Pension Plans [Member]
Retirement Benefits Disclosure [Line Items]
Defined benefit plan, target allocation percentage of assets						10.00%