Retirement Plans and Postretirement Medical Benefits (Fair Value Measurements of Plan Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 16,820	$ 17,132
United States | Total plan assets at fair value
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,549,157	1,601,786
United States | Total plan assets at fair value | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	202,416	322,851
United States | Total plan assets at fair value | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,384,514	1,409,106
United States | Total plan assets at fair value | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	77,494	69,347
United States | Total plan assets at fair value | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,664,424	1,801,304
United States | Money market funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
United States | Money market funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,725	14,442
United States | Money market funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
United States | Money market funds | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,725	14,442
United States | Equities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
United States | Equities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	195,037	323,311
United States | Equities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
United States | Equities | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	195,037	323,311
United States | Commingled fixed income securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
United States | Commingled fixed income securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	229,300	264,896
United States | Commingled fixed income securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
United States | Commingled fixed income securities | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	229,300	264,896
United States | Government and related securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	202,416	322,851
United States | Government and related securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	26,582	22,549
United States | Government and related securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
United States | Government and related securities | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	228,998	345,400
United States | Corporate debt securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
United States | Corporate debt securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	771,529	586,998
United States | Corporate debt securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
United States | Corporate debt securities | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	771,529	586,998
United States | Mortgage-backed /asset-backed securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
United States | Mortgage-backed /asset-backed securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12,486	45,861
United States | Mortgage-backed /asset-backed securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
United States | Mortgage-backed /asset-backed securities | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	12,486	45,861
United States | Real estate
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	52,491	45,275	$ 45,335
United States | Real estate | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
United States | Real estate | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
United States | Real estate | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	77,494	69,347
United States | Real estate | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	77,494	69,347
United States | Diversified growth funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	52,169	50,750	$ 47,621
United States | Securities lending collateral | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
United States | Securities lending collateral | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	145,855	151,049
United States | Securities lending collateral | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
United States | Securities lending collateral | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	145,855	151,049
United States | Cash
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	20,569	15,449
United States | Securities lending payable
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	145,855	151,049
United States | Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	6,801	81,050
Foreign | Total plan assets at fair value
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	737,443	742,639
Foreign | Total plan assets at fair value | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Foreign | Total plan assets at fair value | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	624,291	639,681
Foreign | Total plan assets at fair value | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	104,660	96,025
Foreign | Total plan assets at fair value | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	728,951	735,706
Foreign | Money market funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Foreign | Money market funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8,577	10,072
Foreign | Money market funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Foreign | Money market funds | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	8,577	10,072
Foreign | Equities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Foreign | Equities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	96,596	166,683
Foreign | Equities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Foreign | Equities | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	96,596	166,683
Foreign | Commingled fixed income securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Foreign | Commingled fixed income securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	431,845	379,656
Foreign | Commingled fixed income securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Foreign | Commingled fixed income securities | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	431,845	379,656
Foreign | Government and related securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Foreign | Government and related securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	46,522	46,268
Foreign | Government and related securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Foreign | Government and related securities | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	46,522	46,268
Foreign | Corporate debt securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Foreign | Corporate debt securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	33,583	37,002
Foreign | Corporate debt securities | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Foreign | Corporate debt securities | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	33,583	37,002
Foreign | Real estate | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Foreign | Real estate | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7,168	0
Foreign | Real estate | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	52,491	45,275
Foreign | Real estate | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	59,659	45,275
Foreign | Diversified growth funds | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Foreign | Diversified growth funds | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	0	0
Foreign | Diversified growth funds | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	52,169	50,750
Foreign | Diversified growth funds | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	52,169	50,750
Foreign | Cash
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	7,966	6,448
Foreign | Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 526	$ 485