Derivative Instruments and Hedging Activities - Fair Value (Details) - USD ($)
$ in Millions |
Sep. 30, 2018 |
Sep. 30, 2017 |
| Derivative [Line Items] |
|
|
| Derivative Asset |
$ 3
|
|
| Derivative Liability |
41
|
|
| Derivatives Designated as Hedging Instruments: |
|
|
| Derivative [Line Items] |
|
|
| Derivative Asset |
3
|
|
| Derivative Liability |
7
|
|
| Derivatives Designated as Hedging Instruments: | Other assets | Interest rate contracts |
|
|
| Derivative [Line Items] |
|
|
| Derivative Asset |
3
|
|
| Derivative Liability |
0
|
|
| Derivatives Designated as Hedging Instruments: | Other current liabilities | Interest rate contracts |
|
|
| Derivative [Line Items] |
|
|
| Derivative Asset |
0
|
|
| Derivative Liability |
7
|
|
| Derivatives Not Designated as Hedging Instruments: | Other liabilities | Warrants |
|
|
| Derivative [Line Items] |
|
|
| Derivative Asset |
0
|
|
| Derivative Liability |
$ 34
|
|
| Predecessor |
|
|
| Derivative [Line Items] |
|
|
| Derivative Asset |
|
$ 0
|
| Derivative Liability |
|
0
|
| Predecessor | Derivatives Designated as Hedging Instruments: |
|
|
| Derivative [Line Items] |
|
|
| Derivative Asset |
|
0
|
| Derivative Liability |
|
0
|
| Predecessor | Derivatives Designated as Hedging Instruments: | Other assets | Interest rate contracts |
|
|
| Derivative [Line Items] |
|
|
| Derivative Asset |
|
0
|
| Derivative Liability |
|
0
|
| Predecessor | Derivatives Designated as Hedging Instruments: | Other current liabilities | Interest rate contracts |
|
|
| Derivative [Line Items] |
|
|
| Derivative Asset |
|
0
|
| Derivative Liability |
|
0
|
| Predecessor | Derivatives Not Designated as Hedging Instruments: | Other liabilities | Warrants |
|
|
| Derivative [Line Items] |
|
|
| Derivative Asset |
|
0
|
| Derivative Liability |
|
$ 0
|