Commitments and Contingent Liabilities Commitments for Jones Act (Details) $ in Millions |
Dec. 31, 2016
USD ($)
|
---|---|
Philly Tankers LLC [Member] | |
Other Commitments [Line Items] | |
Purchase Obligation, Due in Next Twelve Months | $ 383 |
Unrecorded Unconditional Purchase Obligation, Due in Next Twelve Months | $ 195 |
Philly Tankers LLC [Member] | |
Other Commitments [Line Items] | |
Number of Vessels | 4 |