Contingent Liabilities (Details Textual) (USD $)	3 Months Ended
	Mar. 31, 2015
Loss Contingencies [Line Items]
Accrued Environmental Loss liabilities	$ 43,000,000
Geismar Incident [Member]
Loss Contingencies [Line Items]
Loss Contingency, Damages Sought, Value	45,000,000
Former Alaska Refinery [Member]
Loss Contingencies [Line Items]
Loss Contingency, Estimate of Possible Loss	32,000,000
Former Operations
Loss Contingencies [Line Items]
Accrued Environmental Loss liabilities	25,000,000
Natural gas underground storage facilities
Loss Contingencies [Line Items]
Accrued Environmental Loss liabilities	8,000,000
Environmental Protection Agency [Member]
Loss Contingencies [Line Items]
Accrued Environmental Loss liabilities	10,000,000
Williams Partners [Member] | General Liability [Member] | Geismar Incident [Member]
Loss Contingencies [Line Items]
Aggregate Annual Limit of Insurance	610,000,000
Insurance deductibles	$ 2,000,000