Commitments and Contingent Liabilities - Asbestos-Related Liabilities (Details) $ in Millions	3 Months Ended	6 Months Ended
	Jun. 30, 2017 USD ($) shares	Jun. 30, 2017 USD ($) payment shares	Feb. 03, 2017 USD ($)	Dec. 31, 2016 USD ($)	Feb. 03, 2014 USD ($)
Other Commitments Chapter 11 [Abstract]
ZAI PD account funding					$ 34.4
ZAI P D Account, Payment on Third Anniversary of Effective Date of Joint Plan			$ 30.0
ZAI P D account, maximum number of contingent deferred payments | payment		10
ZAI P D account, deferred payments, each year for twenty years		$ 8.0
Period in which ZAI PD contingent deferred payments will be made		20 years
Minimum ZAI P D account assets for condition in relation to contingent obligation payments	$ 10.0	$ 10.0
Frequency of PD trust payments		6 months
Number of shares issuable under warrant (in shares) | shares	77,372,257	77,372,257
Environmental remediation
Estimated liability for environmental investigative and remediation costs	$ 68.3	$ 68.3		$ 66.3
Vermiculite Related Matters [Member]
Environmental remediation
Accrual for Environmental Investigative and Remediation Costs, Period Increase (Decrease)	4.3
Estimated liability for environmental investigative and remediation costs	26.8	26.8		31.2
Non-Vermiculite Related Matters [Member]
Environmental remediation
Accrual for Environmental Investigative and Remediation Costs, Period Increase (Decrease)	8.9
Estimated liability for environmental investigative and remediation costs	41.5	$ 41.5		$ 35.1
Non-Vermiculite Related Remediation [Member]
Environmental remediation
Accrual for Environmental Investigative and Remediation Costs, Period Increase (Decrease)	$ 7.2