Retirement Benefits - Obligations and Funded Status (Details) - USD ($) $ in Millions		12 Months Ended
	Oct. 08, 2019	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Noncurrent asset		$ 18.4	$ 0.0
Total
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year		1,427.8	1,145.2
Service cost		9.1	9.7	$ 9.9
Interest cost		33.2	38.3	44.5
Participant contributions		0.4	0.7
Plan amendments		(0.7)	0.3
Plan combinations		7.6	1.0
Acquisitions		5.9	132.5
Curtailment		(1.1)	(1.5)
Settlements		(14.0)	(0.7)
Benefits paid		(60.7)	(65.6)
Actuarial (gains) losses		(59.6)	141.4
Foreign currency exchange effects		(16.2)	26.5
Benefit obligation at end of year		1,331.7	1,427.8	1,145.2
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year		1,102.9	914.4
Return on assets – actual		86.7	140.3
Participant contributions		0.4	0.7
Plan combinations		5.0	1.0
Employer contributions		13.2	14.8
Acquisitions		0.0	80.3
Settlements		(14.0)	(0.7)
Benefits paid		(60.7)	(65.6)
Foreign currency exchange effects		(8.4)	17.7
Fair value of plan assets at end of year		1,125.1	1,102.9	914.4
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status		(206.6)	(324.9)
Noncurrent asset		18.4
Current liability, included in accrued liabilities		5.7	2.8
Noncurrent liability		219.3	322.1
Net pension liability		206.6	324.9
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Beginning of year - net gains and losses		(403.9)	(378.1)
Net actuarial gains (losses) arising during the year		69.7	(59.4)
Reclassification adjustment for amortization of prior actuarial losses included in net income (loss)		43.9	36.1
Foreign currency exchange effects		0.7	(2.5)
End of year - net gains and losses		(289.6)	(403.9)	(378.1)
Benefit plan prior service cost recognized in accumulated other comprehensive income (loss):
Beginning of year - net prior service (cost) credit		(0.6)	(0.5)
Prior service credit (cost) from plan amendments during the year		0.7	(0.3)
Foreign currency exchange effects		0.0	0.2
End of year - net prior service (cost) credit		0.1	(0.6)	(0.5)
Retirement benefits other than pension
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year		558.0	536.7
Service cost		0.1	0.1	0.2
Interest cost		13.0	16.5	21.1
Benefits paid		(31.0)	(33.1)
Actuarial (gains) losses		(29.0)	40.3
Foreign currency exchange effects		(0.7)	(2.5)
Benefit obligation at end of year		510.4	558.0	536.7
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year		168.0	177.9
Return on assets – actual		32.9	14.1
Plan combinations		0.0	1.7
Employer contributions		8.1	7.4
Benefits paid		(31.0)	(33.1)
Fair value of plan assets at end of year		178.0	168.0	177.9
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status		(332.4)	(390.0)
Current liability, included in accrued liabilities		10.2	10.3
Noncurrent liability		322.2	379.7
Net pension liability		332.4	390.0
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Beginning of year - net gains and losses		(310.4)	(297.3)
Net actuarial gains (losses) arising during the year		49.6	(39.2)
Reclassification adjustment for amortization of prior actuarial losses included in net income (loss)		26.5	24.8
Foreign currency exchange effects		0.3	1.3
End of year - net gains and losses		(234.0)	(310.4)	(297.3)
Benefit plan prior service cost recognized in accumulated other comprehensive income (loss):
Beginning of year - net prior service (cost) credit		24.2	29.4
Reclassification adjustment for amortization of prior service cost included in net income (loss)		(5.0)	(5.0)
Foreign currency exchange effects		0.0	(0.2)
End of year - net prior service (cost) credit		19.2	24.2	29.4
U.S. Plans
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year		908.0	826.8
Service cost		0.0	0.0	0.0
Interest cost		21.1	26.7	34.1
Participant contributions		0.0	0.0
Plan amendments		0.0	0.0
Plan combinations		0.0	0.0
Settlements		0.0	0.0
Benefits paid		(46.9)	(44.0)
Actuarial (gains) losses		(42.7)	98.5
Foreign currency exchange effects		0.0	0.0
Benefit obligation at end of year		839.5	908.0	826.8
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year		747.1	699.3
Return on assets – actual		63.9	91.2
Participant contributions		0.0	0.0
Plan combinations		0.0	0.0
Employer contributions		0.7	0.6
Settlements		0.0	0.0
Benefits paid		(46.9)	(44.0)
Foreign currency exchange effects		0.0	0.0
Fair value of plan assets at end of year		764.8	747.1	699.3
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status		(74.7)	(160.9)
Current liability, included in accrued liabilities		0.6	0.6
Noncurrent liability		74.1	160.3
Net pension liability		74.7	160.9
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Beginning of year - net gains and losses		(321.5)	(296.6)
Net actuarial gains (losses) arising during the year		59.2	(53.5)
Reclassification adjustment for amortization of prior actuarial losses included in net income (loss)		34.0	28.6
Foreign currency exchange effects		0.0	0.0
End of year - net gains and losses		(228.3)	(321.5)	(296.6)
Benefit plan prior service cost recognized in accumulated other comprehensive income (loss):
Beginning of year - net prior service (cost) credit		0.0	0.0
Prior service credit (cost) from plan amendments during the year		0.0	0.0
Foreign currency exchange effects		0.0	0.0
End of year - net prior service (cost) credit		0.0	0.0	0.0
U.S. Plans | Actuarial Gains (Losses) - Change in Discount Rate
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Net actuarial gains (losses) arising during the year		41.0	(93.0)
U.S. Plans | Actuarial Gains (Losses) - Change in Census Data
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Net actuarial gains (losses) arising during the year			(5.0)
U.S. Plans | Actuarial Gains (Losses) - Asset Return Different from Expected
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Net actuarial gains (losses) arising during the year		17.0	45.0
U.S. Plans | Total
Changes in the benefit obligation [Roll Forward]
Settlements	$ (54.0)
Non-U.S. Plans
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year		519.8	318.4
Service cost		9.1	9.7	9.9
Interest cost		12.1	11.6	10.4
Participant contributions		0.4	0.7
Plan amendments		(0.7)	0.3
Plan combinations		7.6	1.0
Acquisitions		5.9	132.5
Curtailment		(1.1)	(1.5)
Settlements		(14.0)	(0.7)
Benefits paid		(13.8)	(21.6)
Actuarial (gains) losses		(16.9)	42.9
Foreign currency exchange effects		(16.2)	26.5
Benefit obligation at end of year		492.2	519.8	318.4
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year		355.8	215.1
Return on assets – actual		22.8	49.1
Participant contributions		0.4	0.7
Plan combinations		5.0	1.0
Employer contributions		12.5	14.2
Acquisitions		0.0	80.3
Settlements		(14.0)	(0.7)
Benefits paid		(13.8)	(21.6)
Foreign currency exchange effects		(8.4)	17.7
Fair value of plan assets at end of year		360.3	355.8	215.1
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status		(131.9)	(164.0)
Noncurrent asset		18.4
Current liability, included in accrued liabilities		5.1	2.2
Noncurrent liability		145.2	161.8
Net pension liability		131.9	164.0
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Beginning of year - net gains and losses		(82.4)	(81.5)
Net actuarial gains (losses) arising during the year		10.5	(5.9)
Reclassification adjustment for amortization of prior actuarial losses included in net income (loss)		9.9	7.5
Foreign currency exchange effects		0.7	(2.5)
End of year - net gains and losses		(61.3)	(82.4)	(81.5)
Benefit plan prior service cost recognized in accumulated other comprehensive income (loss):
Beginning of year - net prior service (cost) credit		(0.6)	(0.5)
Prior service credit (cost) from plan amendments during the year		0.7	(0.3)
Foreign currency exchange effects		0.0	0.2
End of year - net prior service (cost) credit		0.1	(0.6)	(0.5)
Non-U.S. Plans | Actuarial Gains (Losses) - Change in Discount Rate
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Net actuarial gains (losses) arising during the year			(45.0)
Non-U.S. Plans | Actuarial Gains (Losses) - Asset Return Different from Expected
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Net actuarial gains (losses) arising during the year		10.0	37.0
UMWA Plans
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year		440.1	424.6
Service cost		0.0	0.0	0.0
Interest cost		9.8	12.7	17.3
Benefits paid		(22.9)	(25.7)
Actuarial (gains) losses		(29.6)	28.5
Foreign currency exchange effects		0.0	0.0
Benefit obligation at end of year		397.4	440.1	424.6
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year		168.0	177.9
Return on assets – actual		32.9	14.1
Plan combinations		0.0	1.7
Benefits paid		(22.9)	(25.7)
Fair value of plan assets at end of year		178.0	168.0	177.9
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status		(219.4)	(272.1)
Current liability, included in accrued liabilities		0.0	0.0
Noncurrent liability		219.4	272.1
Net pension liability		219.4	272.1
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Beginning of year - net gains and losses		(230.1)	(219.2)
Net actuarial gains (losses) arising during the year		50.2	(27.4)
Reclassification adjustment for amortization of prior actuarial losses included in net income (loss)		17.5	16.5
Foreign currency exchange effects		0.0	0.0
End of year - net gains and losses		(162.4)	(230.1)	(219.2)
Benefit plan prior service cost recognized in accumulated other comprehensive income (loss):
Beginning of year - net prior service (cost) credit		23.3	28.0
Reclassification adjustment for amortization of prior service cost included in net income (loss)		(4.7)	(4.7)
Foreign currency exchange effects		0.0	0.0
End of year - net prior service (cost) credit		18.6	23.3	28.0
UMWA Plans | Actuarial Gains (Losses) - Change in Discount Rate
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Net actuarial gains (losses) arising during the year		23.0	(37.0)
UMWA Plans | Actuarial Gains (Losses) - Asset Return Different from Expected
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Net actuarial gains (losses) arising during the year		21.0
UMWA Plans | Actuarial Gains (Losses) - Change in Claims Experience
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Net actuarial gains (losses) arising during the year		9.0	10.0
Black Lung and Other Plans
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year		117.9	112.1
Service cost		0.1	0.1	0.2
Interest cost		3.2	3.8	3.8
Benefits paid		(8.1)	(7.4)
Actuarial (gains) losses		0.6	11.8
Foreign currency exchange effects		(0.7)	(2.5)
Benefit obligation at end of year		113.0	117.9	112.1
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year		0.0	0.0
Return on assets – actual		0.0	0.0
Employer contributions		8.1	7.4
Benefits paid		(8.1)	(7.4)
Fair value of plan assets at end of year		0.0	0.0	0.0
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status		(113.0)	(117.9)
Current liability, included in accrued liabilities		10.2	10.3
Noncurrent liability		102.8	107.6
Net pension liability		113.0	117.9
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Beginning of year - net gains and losses		(80.3)	(78.1)
Net actuarial gains (losses) arising during the year		(0.6)	(11.8)
Reclassification adjustment for amortization of prior actuarial losses included in net income (loss)		9.0	8.3
Foreign currency exchange effects		0.3	1.3
End of year - net gains and losses		(71.6)	(80.3)	(78.1)
Benefit plan prior service cost recognized in accumulated other comprehensive income (loss):
Beginning of year - net prior service (cost) credit		0.9	1.4
Reclassification adjustment for amortization of prior service cost included in net income (loss)		(0.3)	(0.3)
Foreign currency exchange effects		0.0	(0.2)
End of year - net prior service (cost) credit		0.6	0.9	$ 1.4
Black Lung and Other Plans | Actuarial Gains (Losses) - Change in Discount Rate
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Net actuarial gains (losses) arising during the year		4.0	(8.0)
Black Lung and Other Plans | Actuarial Gains (Losses) - Change in Census Data
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Net actuarial gains (losses) arising during the year		(10.0)	(5.0)
Black Lung and Other Plans | Actuarial Gains (Losses) - Change in Claims Experience
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Net actuarial gains (losses) arising during the year		$ 4.0	$ 3.0