Derivative Instruments - Summary of Effects of Undesignated Derivatives on Consolidated Statements of Operations (Details) - Not Designated as Hedging Instrument - USD ($) $ in Millions |
3 Months Ended | 9 Months Ended | ||
|---|---|---|---|---|
Sep. 30, 2019 |
Sep. 30, 2018 |
Sep. 30, 2019 |
Sep. 30, 2018 |
|
| Interest rate derivatives | ||||
| Derivative Instruments, Gain (Loss) [Line Items] | ||||
| Gain on derivatives | $ 0 | $ 0 | $ (1) | $ 4 |
| Energy derivative | ||||
| Derivative Instruments, Gain (Loss) [Line Items] | ||||
| Electricity sales | 0 | 2 | 0 | (2) |
| Foreign currency forward contracts | ||||
| Derivative Instruments, Gain (Loss) [Line Items] | ||||
| Gain on derivatives | $ 3 | $ 1 | $ 4 | $ 12 |