Related-Party Transactions Related-Party Transactions, Summary of Transactions Narrative (Details) - USD ($) $ in Millions |
3 Months Ended | ||||||
|---|---|---|---|---|---|---|---|
Mar. 31, 2017 |
Mar. 31, 2016 |
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| Revenue from Related Parties | [1] | $ 203 | $ 169 | ||||
| Related Party Transaction, Expenses from Transactions with Related Party | [2] | 39 | 35 | ||||
| Related Party Transaction, Selling, General and Administrative Expenses from Transactions with Related Party | $ 20 | $ 17 | |||||
| Concentration Risk, Percentage | 48.00% | 56.00% | |||||
| Volume Gains (Losses) Value | $ 3 | $ 1 | |||||
| Cost of Reimbursable Expense | 2 | 6 | |||||
| Partner to Tesoro [Member] | Omnibus Agreement | |||||||
| Payment for Administrative Fees | 11 | ||||||
| Tesoro to Partner [Member] | Secondment and Logistics Services Agreement | |||||||
| Long-term Purchase Commitment, Amount | $ 5 | $ 5 | |||||
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