Related Party Transactions - Sales to Related Parties (Details) - USD ($) $ in Millions |
3 Months Ended | |
|---|---|---|
Mar. 31, 2018 |
Mar. 31, 2017 |
|
| Related Party Transaction [Line Items] | ||
| Sales to related parties | $ 172 | $ 154 |
| PFJ Southeast | ||
| Related Party Transaction [Line Items] | ||
| Sales to related parties | 169 | 151 |
| Other equity method investees | ||
| Related Party Transaction [Line Items] | ||
| Sales to related parties | $ 3 | $ 3 |