Intangible Assets - Narrative (Details) - USD ($)
$ in Millions |
2 Months Ended |
9 Months Ended |
10 Months Ended |
12 Months Ended |
Dec. 15, 2017 |
Jun. 30, 2017 |
Jun. 30, 2016 |
Sep. 30, 2018 |
Sep. 30, 2018 |
Sep. 30, 2017 |
Sep. 30, 2016 |
| Finite-Lived Intangible Assets [Line Items] |
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| Amortization of intangible assets |
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$ 262
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| Impairment of indefinite-lived intangible assets |
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$ 0
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| Minimum |
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| Finite-Lived Intangible Assets [Line Items] |
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| Intangible asset, useful life |
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1 year
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| Maximum |
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| Finite-Lived Intangible Assets [Line Items] |
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| Intangible asset, useful life |
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20 years
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| Technology-Based Intangible Assets | Minimum |
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| Finite-Lived Intangible Assets [Line Items] |
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| Intangible asset, useful life |
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1 year
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| Technology-Based Intangible Assets | Maximum |
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| Finite-Lived Intangible Assets [Line Items] |
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| Intangible asset, useful life |
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10 years
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| Technology-Based Intangible Assets | Weighted Average |
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| Finite-Lived Intangible Assets [Line Items] |
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| Intangible asset, useful life |
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4 years 11 months 1 day
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| Customer Relationships | Minimum |
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| Finite-Lived Intangible Assets [Line Items] |
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| Intangible asset, useful life |
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1 year
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| Customer Relationships | Maximum |
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| Finite-Lived Intangible Assets [Line Items] |
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| Intangible asset, useful life |
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19 years
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| Customer Relationships | Weighted Average |
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| Finite-Lived Intangible Assets [Line Items] |
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| Intangible asset, useful life |
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13 years 9 months 25 days
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| Trade Names |
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| Finite-Lived Intangible Assets [Line Items] |
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| Intangible asset, useful life |
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10 years
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| Trade Names | Weighted Average |
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| Finite-Lived Intangible Assets [Line Items] |
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| Intangible asset, useful life |
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9 years 2 months 16 days
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| Predecessor |
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| Finite-Lived Intangible Assets [Line Items] |
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| Amortization of intangible assets |
$ 13
|
|
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|
$ 224
|
$ 256
|
| Cost |
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|
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|
545
|
|
| Impairment of indefinite-lived intangible assets |
$ 0
|
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65
|
$ 100
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| Trademarks and trade names | Predecessor |
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| Finite-Lived Intangible Assets [Line Items] |
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| Indefinite-lived intangible assets, fair value |
|
$ 190
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$ 255
|
|
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| Cost |
|
255
|
355
|
|
|
$ 545
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| Impairment of indefinite-lived intangible assets |
|
$ 65
|
$ 100
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