Retirement Benefits - Obligations and Funded Status (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Defined Benefit Plan, Funded Status of Plan [Abstract]
Noncurrent asset	$ (28.6)	$ (21.9)
US Plans [Member]
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year	1,031.3	990.7
Service cost	0	0	0
Interest cost	42.2	43.8	46.2
Participant contributions	0	0
Plan amendments	0	0
Curtailments	0	0
Settlements	(0.5)	(13.9)
Acquisition	0	0
Benefits paid	(43.6)	(42.3)
Actuarial (gains) losses	(94.5)	53.0
Foreign currency exchange effects	0	0
Benefit obligation at end of year	934.9	1,031.3	990.7
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	756.3	685.4
Return on assets - actual	85.5	89.9
Participant contributions	0	0
Employer contributions	14.1	37.2
Settlements	(0.5)	(13.9)
Acquisition	0	0
Benefits paid	(43.6)	(42.3)
Foreign currency effects	0	0
Fair value of plan assets at end of year	811.8	756.3	685.4
Defined Benefit Plan, Funded Status of Plan [Abstract]
Funded status	(123.1)	(275.0)
Noncurrent asset	0	0
Current liability, included in accrued liabilities	0.8	0.9
Noncurrent liability	122.3	274.1
Net pension liability	123.1	275.0
Defined Benefit Plan Change In Net Actuarial Gains And Losses In Other Comprehensive Income [Roll Forward]
Beginning of year - net gains and losses	(491.9)	(513.3)
Net experience losses arising during the year	123.1	(23.1)
Reclassification adjustment for amortization of prior experience losses included in net income	45.2	44.5
End of year - net gains and losses	(323.6)	(491.9)	(513.3)
Defined Benefit Plan Change In Net Prior Service Cost Credit In Other Comprehensive Income [Roll Forward]
Beginning of year - net prior service (cost) credit	0	0
Prior service (cost) credit from plan amendments during the year	0	0
Reclassification adjustment for amortization of prior service cost included in net income	0	0
End of year - net prior service (cost) credit	0	0	0
Non-US Plans [Member]
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year	392.3	306.9
Service cost	15.0	11.1	10.2
Interest cost	19.1	19.1	16.9
Participant contributions	3.8	3.5
Plan amendments	(4.9)	11.7
Curtailments	(0.2)	(0.4)
Settlements	(2.0)	(3.2)
Acquisition	0	0
Benefits paid	(18.8)	(22.0)
Actuarial (gains) losses	(8.0)	54.9
Foreign currency exchange effects	(5.9)	10.7
Benefit obligation at end of year	390.4	392.3	306.9
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	283.0	230.5
Return on assets - actual	16.6	34.7
Participant contributions	3.8	3.5
Employer contributions	40.1	32.8
Settlements	(2.0)	(3.2)
Acquisition	0	0
Benefits paid	(18.8)	(22.0)
Foreign currency effects	(0.7)	6.7
Fair value of plan assets at end of year	322.0	283.0	230.5
Defined Benefit Plan, Funded Status of Plan [Abstract]
Funded status	(68.4)	(109.3)
Noncurrent asset	(28.6)	(21.9)
Current liability, included in accrued liabilities	4.5	7.5
Noncurrent liability	92.5	123.7
Net pension liability	68.4	109.3
Defined Benefit Plan Change In Net Actuarial Gains And Losses In Other Comprehensive Income [Roll Forward]
Beginning of year - net gains and losses	(59.7)	(34.6)
Net experience losses arising during the year	11.7	(32.4)
Reclassification adjustment for amortization of prior experience losses included in net income	8.8	7.3
End of year - net gains and losses	(39.2)	(59.7)	(34.6)
Defined Benefit Plan Change In Net Prior Service Cost Credit In Other Comprehensive Income [Roll Forward]
Beginning of year - net prior service (cost) credit	(15.8)	(6.1)
Prior service (cost) credit from plan amendments during the year	4.9	(11.7)
Reclassification adjustment for amortization of prior service cost included in net income	0.7	2.0
End of year - net prior service (cost) credit	(10.2)	(15.8)	(6.1)
UMWA Plans Postretirement Medical [Member]
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year	525.3	529.6
Service cost	0	0	0
Interest cost	19.7	22.3	24.0
Plan amendments	(55.7)	0
Benefits paid	(34.2)	(35.7)
Medicare subsidy received	3.1	3.2
Actuarial (gains) losses	(31.7)	5.9
Foreign currency exchange effects	0	0
Benefit obligation at end of year	426.5	525.3	529.6
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	268.7	268.0
Return on assets - actual	45.8	33.5
Employer contributions	1.0	0
Benefits paid	(34.2)	(36.0)
Medicare subsidy received	3.1	3.2
Fair value of plan assets at end of year	284.4	268.7	268.0
Defined Benefit Plan, Funded Status of Plan [Abstract]
Funded status	(142.1)	(256.6)
Current liability, included in accrued liabilities	0	0
Noncurrent liability	142.1	256.6
Net pension liability	142.1	256.6
Defined Benefit Plan Change In Net Actuarial Gains And Losses In Other Comprehensive Income [Roll Forward]
Beginning of year - net gains and losses	(295.7)	(323.0)
Net experience losses arising during the year	(56.7)	(6.3)
Reclassification adjustment for amortization of prior experience losses included in net income	19.6	21.0
End of year - net gains and losses	(219.4)	(295.7)	(323.0)
Defined Benefit Plan Change In Net Prior Service Cost Credit In Other Comprehensive Income [Roll Forward]
Beginning of year - net prior service (cost) credit	0	0
Prior service (cost) credit from plan amendments during the year	55.7	0
Reclassification adjustment for amortization of prior service cost included in net income	0	0
End of year - net prior service (cost) credit	55.7	0	0
Black Lung And Other Plans Postretirement [Member]
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year	53.0	60.9
Service cost	0.3	0.6
Interest cost	1.9	2.8
Plan amendments	0	(1.9)
Benefits paid	(7.1)	(6.6)
Medicare subsidy received	0	0
Actuarial (gains) losses	0.8	(2.2)
Foreign currency exchange effects	0	(0.6)
Benefit obligation at end of year	48.9	53.0
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	0	0
Return on assets - actual	0	0
Employer contributions	7.1	6.6
Benefits paid	(7.1)	(6.6)
Medicare subsidy received	0	0
Fair value of plan assets at end of year	0	0
Defined Benefit Plan, Funded Status of Plan [Abstract]
Funded status	(48.9)	(53.0)
Current liability, included in accrued liabilities	5.0	5.0
Noncurrent liability	43.9	48.0
Net pension liability	48.9	53.0
Defined Benefit Plan Change In Net Actuarial Gains And Losses In Other Comprehensive Income [Roll Forward]
Beginning of year - net gains and losses	(6.2)	(9.9)
Net experience losses arising during the year	0.8	(2.2)
Reclassification adjustment for amortization of prior experience losses included in net income	0.7	1.5
End of year - net gains and losses	(6.3)	(6.2)
Defined Benefit Plan Change In Net Prior Service Cost Credit In Other Comprehensive Income [Roll Forward]
Beginning of year - net prior service (cost) credit	(9.4)	(13.3)
Prior service (cost) credit from plan amendments during the year	0	1.9
Reclassification adjustment for amortization of prior service cost included in net income	1.7	2.0
End of year - net prior service (cost) credit	(7.7)	(9.4)
Pension plan [Member]
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year	1,423.6	1,297.6
Service cost	15.0	11.1	10.2
Interest cost	61.3	62.9	63.1
Participant contributions	3.8	3.5
Plan amendments	(4.9)	11.7
Curtailments	(0.2)	(0.4)
Settlements	(2.5)	(17.1)
Acquisition	0	0
Benefits paid	(62.4)	(64.3)
Actuarial (gains) losses	(102.5)	107.9
Foreign currency exchange effects	(5.9)	10.7
Benefit obligation at end of year	1,325.3	1,423.6	1,297.6
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	1,039.3	915.9
Return on assets - actual	102.1	124.6
Participant contributions	3.8	3.5
Employer contributions	54.2	70.0
Settlements	(2.5)	(17.1)
Acquisition	0	0
Benefits paid	(62.4)	(64.3)
Foreign currency effects	(0.7)	6.7
Fair value of plan assets at end of year	1,133.8	1,039.3	915.9
Defined Benefit Plan, Funded Status of Plan [Abstract]
Funded status	(191.5)	(384.3)
Noncurrent asset	(28.6)	(21.9)
Current liability, included in accrued liabilities	5.3	8.4
Noncurrent liability	214.8	397.8
Net pension liability	191.5	384.3
Defined Benefit Plan Change In Net Actuarial Gains And Losses In Other Comprehensive Income [Roll Forward]
Beginning of year - net gains and losses	(551.6)	(547.9)
Net experience losses arising during the year	134.8	(55.5)
Reclassification adjustment for amortization of prior experience losses included in net income	54.0	51.8
End of year - net gains and losses	(362.8)	(551.6)	(547.9)
Defined Benefit Plan Change In Net Prior Service Cost Credit In Other Comprehensive Income [Roll Forward]
Beginning of year - net prior service (cost) credit	(15.8)	(6.1)
Prior service (cost) credit from plan amendments during the year	4.9	(11.7)
Reclassification adjustment for amortization of prior service cost included in net income	0.7	2.0
End of year - net prior service (cost) credit	(10.2)	(15.8)	(6.1)
Retirement benefits other than pension [Member]
Changes in the benefit obligation [Roll Forward]
Benefit obligation at beginning of year	578.3	590.5
Service cost	0.3	0.6	0
Interest cost	21.6	25.1	26.8
Plan amendments	(55.7)	(1.9)
Benefits paid	(41.3)	(42.3)
Medicare subsidy received	3.1	3.2
Actuarial (gains) losses	(30.9)	3.7
Foreign currency exchange effects	0	(0.6)
Benefit obligation at end of year	475.4	578.3	590.5
Changes in plan assets [Roll Forward]
Fair value of plan assets at beginning of year	268.7	268.0
Return on assets - actual	45.8	33.5
Employer contributions	8.1	6.6
Benefits paid	(41.3)	(42.6)
Medicare subsidy received	3.1	3.2
Fair value of plan assets at end of year	284.4	268.7	268.0
Defined Benefit Plan, Funded Status of Plan [Abstract]
Funded status	(191.0)	(309.6)
Current liability, included in accrued liabilities	5.0	5.0
Noncurrent liability	186.0	304.6
Net pension liability	191.0	309.6
Defined Benefit Plan Change In Net Actuarial Gains And Losses In Other Comprehensive Income [Roll Forward]
Beginning of year - net gains and losses	(301.9)	(332.9)
Net experience losses arising during the year	(55.9)	(8.5)
Reclassification adjustment for amortization of prior experience losses included in net income	20.3	22.5
End of year - net gains and losses	(225.7)	(301.9)	(332.9)
Defined Benefit Plan Change In Net Prior Service Cost Credit In Other Comprehensive Income [Roll Forward]
Beginning of year - net prior service (cost) credit	(9.4)	(13.3)
Prior service (cost) credit from plan amendments during the year	55.7	1.9
Reclassification adjustment for amortization of prior service cost included in net income	1.7	2.0
End of year - net prior service (cost) credit	$ 48.0	$ (9.4)	$ (13.3)