Commitments and Contingencies Claims Rollforward (Details)		12 Months Ended
		Dec. 31, 2017 USD ($) Asbestos_claims	Dec. 31, 2016 USD ($) Asbestos_claims	Dec. 31, 2015 USD ($) Asbestos_claims
Commitments and Contingencies Disclosure [Abstract]
Claims unresolved, beginning of period	[1]	20,567	20,583	21,681
Claims filed	[1],[2]	4,543	5,163	4,821
Claims resolved	[1],[3]	(7,373)	(5,179)	(5,919)
Claims unresolved, end of period	[1]	17,737	20,567	20,583
Average cost of resolved claims | $	[4]	$ 6,154	$ 8,872	$ 6,056

[1] Excludes claims filed by one legal firm that have been “administratively dismissed.”

[2] Claims filed include all asbestos claims for which notification has been received or a file has been opened.

[3] Claims resolved include all asbestos claims that have been settled, dismissed or that are in the process of being settled or dismissed based upon agreements or understandings in place with counsel for the claimants.

[4] Excludes claims settled in Mississippi for which the majority of claims have historically been resolved for no payment and insurance recoveries.