Related-Party Transactions Related-Party Transactions, Summary of Affiliate Transactions (Details) - USD ($) $ / shares in Units, $ in Millions |
3 Months Ended | 9 Months Ended | ||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
Nov. 14, 2016 |
Oct. 18, 2016 |
Sep. 30, 2016 |
Jun. 30, 2016 |
Mar. 31, 2016 |
Dec. 31, 2015 |
Sep. 30, 2015 |
Sep. 30, 2016 |
Sep. 30, 2015 |
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| Concentration Risk, Percentage | 60.00% | 54.00% | 58.00% | 55.00% | ||||||||||||||
| Revenue from Related Parties | [1],[2] | $ 184 | $ 152 | $ 521 | $ 454 | |||||||||||||
| Related Party Transaction, Expenses from Transactions with Related Party | 40 | 33 | 113 | 93 | ||||||||||||||
| Related Party Gain (Loss) On Settlement And Reimbursements | [3] | 5 | 12 | 17 | 31 | |||||||||||||
| Related Party Transaction, Selling, General and Administrative Expenses from Transactions with Related Party | 18 | 16 | 51 | 51 | ||||||||||||||
| Volume Gains (Losses) Value | 2 | 2 | 5 | 6 | ||||||||||||||
| Cost of Reimbursable Expense | $ 3 | $ 10 | 12 | $ 25 | ||||||||||||||
| Distribution Made to Limited Partner, Cash Distributions Declared | $ 175 | |||||||||||||||||
| Distribution Made to Limited Partner, Distributions Declared, Per Unit | $ 0.842 | $ 0.810 | $ 0.780 | |||||||||||||||
| Distribution Made to Limited Partner, Distribution Date | Aug. 12, 2016 | May 13, 2016 | Feb. 12, 2016 | |||||||||||||||
| Subsequent Event | ||||||||||||||||||
| Distribution Made to Limited Partner, Cash Distributions Declared | $ 71 | |||||||||||||||||
| Distribution Made to Limited Partner, Declaration Date | Oct. 18, 2016 | |||||||||||||||||
| Distribution Made to Limited Partner, Distributions Declared, Per Unit | [4] | $ 0.875 | ||||||||||||||||
| Distribution Made to Limited Partner, Distribution Date | [4] | Nov. 14, 2016 | ||||||||||||||||
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