Retirement Plans and Postretirement Medical Benefits (Fair Value Measurements of Plan Assets) (Details) - USD ($) $ in Thousands	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Fair Value Measured at Net Asset Value Per Share
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 10,416	$ 16,820
United States | Total plan assets at fair value
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,161,361	1,549,157
United States | Total plan assets at fair value | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	114,084	202,416
United States | Total plan assets at fair value | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,057,547	1,384,514
United States | Total plan assets at fair value | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	91,500	77,494
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	1,263,131	1,664,424
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	10,623	3,725
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	10,623	3,725
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	137,505	195,037
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	137,505	195,037
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	220,281	229,300
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	220,281	229,300
United States | Government and related securities | Level 1
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	114,084	202,416
United States | Government and related securities | Level 2
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	21,479	26,582
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	135,563	228,998
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	527,407	771,529
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	527,407	771,529
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	26,450	12,486
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	26,450	12,486
United States | Real estate
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	42,980	52,491	$ 45,275
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	91,500	77,494
United States | Real estate | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	91,500	77,494
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	113,802	145,855
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	113,802	145,855
United States | Diversified growth funds
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	24,394	52,169	$ 50,750
United States | Cash
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	3,525	20,569
United States | Securities lending payable
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	113,802	145,855
United States | Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	1,909	6,801
Foreign | Total plan assets at fair value
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	438,403	737,443
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	365,061	624,291
Foreign | Total plan assets at fair value | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	67,374	104,660
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	432,435	728,951
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	8,338	8,577
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	8,338	8,577
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	42,717	96,596
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	42,717	96,596
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	247,337	431,845
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	247,337	431,845
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	35,887	46,522
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	35,887	46,522
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	26,336	33,583
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	26,336	33,583
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	4,446	7,168
Foreign | Real estate | Level 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	42,980	52,491
Foreign | Real estate | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	47,426	59,659
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	24,394	52,169
Foreign | Diversified growth funds | Fair Value, Inputs, Level 1, 2 and 3
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	24,394	52,169
Foreign | Cash
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	5,485	7,966
Foreign | Other
Defined Benefit Plan Disclosure [Line Items]
Fair value of plan assets	$ 483	$ 526