Contingencies (Details) - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2019	Dec. 31, 1993
Loss Contingencies [Line Items]
Site Contingency, Names of Other Potentially Responsible Parties	100
Loss Contingency, Damages Sought, Value	$ 1,200
Loss Contingency, Range of Possible Loss, Portion Not Accrued	500
Investment in Trojan		87.00%
Class action damages sought	260
Loss Contingency, Estimate of Possible Loss	1,700
Environmental Remediation Expense	6
Litigation Settlement, Expense	115
Minimum [Member]
Loss Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss	$ 1,100