Retirement Benefits - Obligations and Funded Status (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Noncurrent asset	$ 15.1	$ 17.7
Total
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year	961.9	1,331.7
Service cost	7.6	8.1	$ 9.1
Interest cost	50.5	36.0	33.2
Participant contributions	0.5	0.3
Plan amendments	0.5	0.1
Plan combinations	0.4	0.9
Curtailment	(0.1)	(0.4)
Settlements	(3.8)	(10.8)
Benefits paid	(66.6)	(61.1)
Divestitures(a)	(3.7)	0.0
Actuarial (gains) losses	48.7	(317.5)
Foreign currency exchange effects	16.4	(25.4)
Benefit obligation at end of year	1,012.3	961.9	1,331.7
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	841.8	1,125.1
Return on assets – actual	80.8	(205.2)
Participant contributions	0.5	0.3
Plan combinations	0.4	0.9
Employer contributions	13.4	15.3
Settlements	(3.8)	(10.8)
Benefits paid	(66.6)	(61.1)
Divestitures	(3.7)	0.0
Foreign currency exchange effects	8.1	(22.7)
Fair value of plan assets at end of year	870.9	841.8	1,125.1
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status	(141.4)	(120.1)
Noncurrent asset	15.1	17.7
Current liability, included in accrued liabilities	8.0	6.8
Noncurrent liability	148.5	131.0
Net pension liability	141.4	120.1
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Beginning of year - net gains and losses	(205.6)	(289.6)
Net actuarial gains (losses) arising during the year	(26.1)	50.9
Reclassification adjustment for amortization of prior actuarial losses included in net income (loss)	3.4	29.4
Foreign currency exchange effects	(2.0)	3.7
End of year - net gains and losses	(230.3)	(205.6)	(289.6)
Benefit plan prior service cost recognized in accumulated other comprehensive income (loss):
Beginning of year - net prior service (cost) credit	(0.1)	0.1
Prior service credit (cost) from plan amendments during the year	(0.5)	(0.1)
Foreign currency exchange effects	(0.1)	(0.1)
End of year - net prior service (cost) credit	(0.7)	(0.1)	0.1
Retirement benefits other than pension
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year	323.1	510.4
Service cost	0.3	0.1	0.1
Interest cost	16.4	14.0	13.0
Plan amendments	0.0	(66.7)
Benefits paid	(27.8)	(29.3)
Actuarial (gains) losses	(7.9)	(105.7)
Foreign currency exchange effects	1.2	0.3
Benefit obligation at end of year	305.3	323.1	510.4
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	139.0	178.0
Return on assets – actual	14.2	(15.1)
Plan combinations	2.7	(3.6)
Employer contributions	8.0	9.0
Benefits paid	(27.8)	(29.3)
Fair value of plan assets at end of year	136.1	139.0	178.0
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status	(169.2)	(184.1)
Current liability, included in accrued liabilities	9.6	9.6
Noncurrent liability	159.6	174.5
Net pension liability	169.2	184.1
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Beginning of year - net gains and losses	(139.4)	(234.0)
Net actuarial gains (losses) arising during the year	11.8	77.4
Reclassification adjustment for amortization of prior actuarial losses included in net income (loss)	9.9	17.3
Foreign currency exchange effects	(0.4)	(0.1)
End of year - net gains and losses	(118.1)	(139.4)	(234.0)
Benefit plan prior service cost recognized in accumulated other comprehensive income (loss):
Beginning of year - net prior service (cost) credit	81.0	19.2
Prior service credit (cost) from plan amendments during the year	0.0	66.7
Reclassification adjustment for amortization of prior service cost included in net income (loss)	(11.1)	(4.9)
Foreign currency exchange effects	0.0	0.0
End of year - net prior service (cost) credit	69.9	81.0	19.2
U.S. Plans
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year	627.2	839.5
Service cost	0.0	0.0	0.0
Interest cost	32.4	22.9	21.1
Participant contributions	0.0	0.0
Plan amendments	0.0	0.0
Plan combinations	0.0	0.0
Curtailment	0.0	0.0
Settlements	0.0	0.0
Benefits paid	(45.2)	(45.0)
Divestitures(a)	0.0	0.0
Actuarial (gains) losses	14.8	(190.2)
Foreign currency exchange effects	0.0	0.0
Benefit obligation at end of year	629.2	627.2	839.5
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	596.3	764.8
Return on assets – actual	59.9	(124.1)
Participant contributions	0.0	0.0
Plan combinations	0.0	0.0
Employer contributions	0.6	0.6
Settlements	0.0	0.0
Benefits paid	(45.2)	(45.0)
Divestitures	0.0	0.0
Foreign currency exchange effects	0.0	0.0
Fair value of plan assets at end of year	611.6	596.3	764.8
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status	(17.6)	(30.9)
Noncurrent asset	0.0	0.0
Current liability, included in accrued liabilities	0.7	0.7
Noncurrent liability	16.9	30.2
Net pension liability	17.6	30.9
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Beginning of year - net gains and losses	(186.7)	(228.3)
Net actuarial gains (losses) arising during the year	(2.1)	17.4
Reclassification adjustment for amortization of prior actuarial losses included in net income (loss)	1.6	24.2
Foreign currency exchange effects	0.0	0.0
End of year - net gains and losses	(187.2)	(186.7)	(228.3)
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	18.0	193.0
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	13.0	173.0
Non-U.S. Plans
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year	334.7	492.2
Service cost	7.6	8.1	9.1
Interest cost	18.1	13.1	12.1
Participant contributions	0.5	0.3
Plan amendments	0.5	0.1
Plan combinations	0.4	0.9
Curtailment	(0.1)	(0.4)
Settlements	(3.8)	(10.8)
Benefits paid	(21.4)	(16.1)
Divestitures(a)	(3.7)	0.0
Actuarial (gains) losses	33.9	(127.3)
Foreign currency exchange effects	16.4	(25.4)
Benefit obligation at end of year	383.1	334.7	492.2
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	245.5	360.3
Return on assets – actual	20.9	(81.1)
Participant contributions	0.5	0.3
Plan combinations	0.4	0.9
Employer contributions	12.8	14.7
Settlements	(3.8)	(10.8)
Benefits paid	(21.4)	(16.1)
Divestitures	(3.7)	0.0
Foreign currency exchange effects	8.1	(22.7)
Fair value of plan assets at end of year	259.3	245.5	360.3
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status	(123.8)	(89.2)
Noncurrent asset	15.1	17.7
Current liability, included in accrued liabilities	7.3	6.1
Noncurrent liability	131.6	100.8
Net pension liability	123.8	89.2
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Beginning of year - net gains and losses	(18.9)	(61.3)
Net actuarial gains (losses) arising during the year	(24.0)	33.5
Reclassification adjustment for amortization of prior actuarial losses included in net income (loss)	1.8	5.2
Foreign currency exchange effects	(2.0)	3.7
End of year - net gains and losses	(43.1)	(18.9)	(61.3)
Benefit plan prior service cost recognized in accumulated other comprehensive income (loss):
Beginning of year - net prior service (cost) credit	(0.1)	0.1
Prior service credit (cost) from plan amendments during the year	(0.5)	(0.1)
Foreign currency exchange effects	(0.1)	(0.1)
End of year - net prior service (cost) credit	(0.7)	(0.1)	0.1
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	30.0	133.0
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	94.0
UMWA Plans
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year	233.9	397.4
Service cost	0.0	0.0	0.0
Interest cost	11.1	10.3	9.8
Plan amendments	0.0	(66.7)
Benefits paid	(19.8)	(20.3)
Actuarial (gains) losses	(11.2)	(86.8)
Foreign currency exchange effects	0.0	0.0
Benefit obligation at end of year	214.0	233.9	397.4
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	139.0	178.0
Return on assets – actual	14.2	(15.1)
Plan combinations	2.7	(3.6)
Employer contributions	0.0	0.0
Benefits paid	(19.8)	(20.3)
Fair value of plan assets at end of year	136.1	139.0	178.0
Defined Benefit Plan, Funded (Unfunded) Status of Plan [Abstract]
Funded status	(77.9)	(94.9)
Current liability, included in accrued liabilities	0.0	0.0
Noncurrent liability	77.9	94.9
Net pension liability	77.9	94.9
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Beginning of year - net gains and losses	(93.9)	(162.4)
Net actuarial gains (losses) arising during the year	15.1	58.5
Reclassification adjustment for amortization of prior actuarial losses included in net income (loss)	5.1	10.0
Foreign currency exchange effects	0.0	0.0
End of year - net gains and losses	(73.7)	(93.9)	(162.4)
Benefit plan prior service cost recognized in accumulated other comprehensive income (loss):
Beginning of year - net prior service (cost) credit	80.7	18.6
Prior service credit (cost) from plan amendments during the year	0.0	66.7
Reclassification adjustment for amortization of prior service cost included in net income (loss)	(11.0)	(4.6)
Foreign currency exchange effects	0.0	0.0
End of year - net prior service (cost) credit	69.7	80.7	18.6
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	5.0	78.0
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	4.0	28.0
UMWA 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		12.0
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		12.0
UMWA Plans | Actuarial Gains (Losses) - Claims Assumptions Updates
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Net actuarial gains (losses) arising during the year	17.0
Black Lung and Other Plans
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year	89.2	113.0
Service cost	0.3	0.1	0.1
Interest cost	5.3	3.7	3.2
Plan amendments	0.0	0.0
Benefits paid	(8.0)	(9.0)
Actuarial (gains) losses	3.3	(18.9)
Foreign currency exchange effects	1.2	0.3
Benefit obligation at end of year	91.3	89.2	113.0
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
Plan combinations	0.0	0.0
Employer contributions	8.0	9.0
Benefits paid	(8.0)	(9.0)
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	(91.3)	(89.2)
Current liability, included in accrued liabilities	9.6	9.6
Noncurrent liability	81.7	79.6
Net pension liability	91.3	89.2
Benefit plan net actuarial losses recognized in accumulated other comprehensive income (loss):
Beginning of year - net gains and losses	(45.5)	(71.6)
Net actuarial gains (losses) arising during the year	(3.3)	18.9
Reclassification adjustment for amortization of prior actuarial losses included in net income (loss)	4.8	7.3
Foreign currency exchange effects	(0.4)	(0.1)
End of year - net gains and losses	(44.4)	(45.5)	(71.6)
Benefit plan prior service cost recognized in accumulated other comprehensive income (loss):
Beginning of year - net prior service (cost) credit	0.3	0.6
Prior service credit (cost) from plan amendments during the year	0.0	0.0
Reclassification adjustment for amortization of prior service cost included in net income (loss)	(0.1)	(0.3)
Foreign currency exchange effects	0.0	0.0
End of year - net prior service (cost) credit	0.2	0.3	$ 0.6
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	$ 2.0	$ 18.0