Derivatives (Open Commodity Derivative Contracts - Refined Product) (Details) - Refined products gal in Thousands	12 Months Ended
	Dec. 31, 2016 gal
Exchange Traded
Derivative [Line Items]
Percentage of derivative contracts expiring in the period	100.00%
Derivative contract expiration date	Mar. 31, 2017
Exchange Traded | Long
Derivative [Line Items]
Notional contracts (in thousands of total gallons)	196,434	[1]
Exchange Traded | Short
Derivative [Line Items]
Notional contracts (in thousands of total gallons)	221,970	[1]
Over the Counter | Short
Derivative [Line Items]
Notional contracts (in thousands of total gallons)	64,212

[1] of the exchange-traded contracts expire in the first quarter of 2017.