Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014		Dec. 31, 2013
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance		$ (931.4)	$ (713.2)		$ (1,029.4)
OCI before reclassifications		(121.7)	(270.3)		236.1
Amounts reclassified from AOCI		38.6	52.1		80.1
Net current-period OCI		(83.1)	(218.2)		316.2
Ending balance		(1,014.5)	(931.4)		(713.2)
Increase (Decrease) in Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Beginning balance		25.0	27.1		23.7
OCI before reclassifications		(5.6)	(2.1)		3.4
Amounts reclassified from AOCI		0.0	0.0		0.0
Net current-period OCI		(5.6)	(2.1)		3.4
Ending balance		19.4	25.0		27.1
Post- retirement benefit plans [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance		(931.5)	(718.9)		(1,030.0)
OCI before reclassifications		(69.6)	(266.4)		241.1
Amounts reclassified from AOCI	[1]	49.9	53.8		70.0
Net current-period OCI		(19.7)	(212.6)		311.1
Ending balance		(951.2)	(931.5)		(718.9)
Increase (Decrease) in Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Beginning balance		0.0	0.0		0.0
OCI before reclassifications		0.0	0.0		0.0
Amounts reclassified from AOCI		0.0	0.0		0.0
Net current-period OCI		0.0	0.0		0.0
Ending balance		0.0	0.0		0.0
Currency translation adjustment [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance		(16.2)	15.3		3.4
OCI before reclassifications		(31.4)	(32.0)		10.4
Amounts reclassified from AOCI		0.0	0.5	[2]	1.5	[2]
Net current-period OCI		(31.4)	(31.5)		11.9
Ending balance		(47.6)	(16.2)		15.3
Increase (Decrease) in Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Beginning balance		25.0	27.1		23.7
OCI before reclassifications		(5.6)	(2.1)		3.4
Amounts reclassified from AOCI	[3]	0.0	0.0		0.0
Net current-period OCI		(5.6)	(2.1)		3.4
Ending balance		19.4	25.0		27.1
Unrealized holding gains on securities [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance		0.0	0.0		(0.1)
OCI before reclassifications		0.0	0.0		0.1
Amounts reclassified from AOCI	[3]	0.0	0.0		0.0
Net current-period OCI		0.0	0.0		0.1
Ending balance		0.0	0.0		0.0
Increase (Decrease) in Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Beginning balance		0.0	0.0		0.0
OCI before reclassifications		0.0	0.0		0.0
Amounts reclassified from AOCI		0.0	0.0		0.0
Net current-period OCI		0.0	0.0		0.0
Ending balance		0.0	0.0		0.0
Derivatives [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance		16.3	(9.6)		(2.7)
OCI before reclassifications		(20.7)	28.1		(15.5)
Amounts reclassified from AOCI	[4]	(11.3)	(2.2)		8.6
Net current-period OCI		(32.0)	25.9		(6.9)
Ending balance		(15.7)	16.3		(9.6)
Increase (Decrease) in Stockholders' Equity Attributable to Noncontrolling Interest [Roll Forward]
Beginning balance		0.0	0.0		0.0
OCI before reclassifications		0.0	0.0		0.0
Amounts reclassified from AOCI		0.0	0.0		0.0
Net current-period OCI		0.0	0.0		0.0
Ending balance		$ 0.0	$ 0.0		$ 0.0

[1] Amounts were included in net periodic benefit cost for pension and other postretirement benefit plans (see Note 12).

[2] Amount in 2014 is included in other income, net, and amount in 2013 is included in discontinued operations as part of the gain on sale of the tungsten materials business (see Note 3).

[3] No amounts were reclassified to earnings.

[4] Amounts related to the effective portion of the derivatives are included in cost of goods sold in the period or periods the hedged item affects earnings. Amounts related to the ineffective portion of the derivatives are presented in selling and administrative expenses on the consolidated statements of operations (see Note 10).