Derivative Instruments and Hedging Activities (Tables)
 12 Months Ended
Sep. 30, 2018
Derivative Instruments and Hedging Activities Disclosure [Abstract]  
Schedule of Assumptions Used
The fair value of the Emergence Date Warrants upon emergence and as of September 30, 2018 (Successor) was recorded in Non-current liabilities - Other liabilities in the Consolidated Balance Sheets, and was determined by using the Black-Scholes option pricing model with the input assumptions summarized below:
 
 
 
As Previously Reported
 
Revised
 
September 30, 2018
 
December 15, 2017
 
December 15, 2017
Expected volatility
50.14
%
 
54.57
%
 
54.38
%
Risk-free interest rates
2.90
%
 
2.20
%
 
2.20
%
Expected remaining life (in years)
4.21

 
5.00

 
5.00

Price per share of common stock
$22.14
 
$14.93
 
$15.16
Schedule of Derivative Instruments in Balance Sheet
The following table summarizes the fair value of the Company's derivatives on a gross basis segregated between those that are designated as hedging instruments and those that are not designated as hedging instruments:
 
 
 
 
Successor
 
 
Predecessor
 
 
 
 
September 30, 2018
 
 
September 30, 2017
(In millions)
 
Balance Sheet Caption
 
Asset
 
Liability
 
 
Asset
 
Liability
Derivatives Designated as Hedging Instruments:
 
 
 
 
 
 
 
 
 
 
 
Interest rate contracts
 
Other assets
 
$
3

 
$
—

 
 
$
—

 
$
—

Interest rate contracts
 
Other current liabilities
 
—

 
7

 
 
—

 
—

 
 
 
 
3

 
7

 
 
—

 
—

 
 
 
 
 
 
 
 
 
 
 
 
Derivatives Not Designated as Hedging Instruments:
 
 
 
 
 
 
 
 
 
 
 
Emergence Date Warrants
 
Other liabilities
 
—

 
34

 
 
—

 
—

Total derivative fair value
 
 
 
$
3

 
$
41

 
 
$
—

 
$
—
Derivatives Designated as Cash Flow Hedges
The following table provides information regarding the location and amount of pre-tax (losses) gains for derivatives designated as cash flow hedges:
 
 
Successor
 
 
Predecessor
 
 
Period from
December 16, 2017
through
September 30, 2018
 
 
Period from
October 1, 2017
through
December 15, 2017
(In millions)
 
Interest Expense
 
Other Comprehensive Income (Loss)
 
 
Interest Expense
 
Other Comprehensive Income (Loss)
Financial Statement Line Item in which Cash Flow Hedges are Recorded
 
$
(169
)
 
$
—

 
 
$
(14
)
 
$
658

 
 
 
 
 
 
 
 
 
 
Impact of cash flow hedging relationships:
 
 
 
 
 
 
 
 
 
Loss recognized in AOCI - on interest rate swaps
 
—

 
(9
)
 
 
—

 
—

Interest expense reclassified from AOCI
 
(6
)
 
6

 
 
—

 
—
Derivatives Not Designated As Hedging Instruments
The following table provides information regarding the pre-tax (losses) gains for derivatives not designated as hedging instruments on the Consolidated Statements of Operations:
 
 
 
 
Successor
 
 
Predecessor
 
 
 
 
Period from December 16, 2017
through
September 30, 2018
 
 
Period from
October 1, 2017
through
December 15, 2017
 
Fiscal year ended September 30,
(In millions)
 
Location of Derivative Pre-tax Gain (Loss)
 
 
 
 
2017
 
2016
Emergence Date Warrants
 
Other income (expense), net
 
$
(17
)
 
 
$
—

 
$
—

 
$
—

Preferred Series B embedded derivative
 
Other income (expense), net
 
—

 
 
—

 
—

 
73

Foreign currency forward contracts
 
Other income (expense), net
 
—

 
 
—

 
—

 
1
Schedule of Outstanding Derivative Positions Presented on a Net Basis
The following table provides information on the Company's derivative positions as if those subject to master netting arrangements were presented on a net basis, allowing for the right to offset by counterparty per the master netting agreements:
 
 
Successor
 
 
Predecessor
 
 
September 30, 2018
 
 
September 30, 2017
(In millions)
 
Asset
 
Liability
 
 
Asset
 
Liability
Gross amounts recognized in the consolidated balance sheet
 
$
3

 
$
41

 
 
$
—

 
$
—

Gross amount subject to offset in master netting arrangements not offset in the Consolidated Balance Sheet
 
(3
)
 
(3
)
 
 
—

 
—

Net amounts
 
$
—

 
$
38

 
 
$
—

 
$
—