Commitments and Contingencies - Narrative (Details) - Record of Decision $ in Millions	1 Months Ended
	Dec. 31, 2014 USD ($) a
Loss Contingencies [Line Items]
Estimated cost of cleanup | $	$ 342
Area of land involving dredging (acres)	105
Area of land involving capping (acres)	24
Area of land involving enhanced natural recover (acres)	48
Total length of cleanup	17 years
Active remediation	7 years
Monitored natural recovery	10 years