Accumulated Other Comprehensive (Loss) Income (Tables)
 12 Months Ended
Sep. 30, 2018
Equity [Abstract]  
Schedule of Accumulated Other Comprehensive Income (Loss)
The components of accumulated other comprehensive (loss) income for the periods indicated were as follows:
(In millions)
Change in Unamortized Pension, Post-retirement and Postemployment Benefit-related Items
 
Foreign Currency Translation
 
Unrealized Loss on Term Loan Interest Rate Swap
 
Other
 
Accumulated Other Comprehensive (Loss) Income
Balance as of October 1, 2015 (Predecessor)
$
(1,368
)
 
$
(15
)
 
$
—

 
$
(1
)
 
$
(1,384
)
Other comprehensive loss before reclassifications
(319
)
 
(18
)
 
—

 
—

 
(337
)
Amounts reclassified to earnings
60

 
—

 
—

 
—

 
60

Balance as of September 30, 2016 (Predecessor)
(1,627
)
 
(33
)
 
—

 
(1
)
 
(1,661
)
Other comprehensive income (loss) before reclassifications
181

 
(39
)
 
—

 
—

 
142

Amounts reclassified to earnings
90

 
—

 
—

 
—

 
90

Provision for income taxes
(19
)
 
—

 
—

 
—

 
(19
)
Balance as of September 30, 2017 (Predecessor)
(1,375
)
 
(72
)
 
—

 
(1
)
 
(1,448
)
Other comprehensive (loss) income before reclassifications
(24
)
 
3

 
—

 
—

 
(21
)
Amounts reclassified to earnings
16

 
—

 
—

 
—

 
16

Pension settlement
721

 
—

 
—

 
—

 
721

Provision for income taxes
(58
)
 
—

 
—

 
—

 
(58
)
Balance as of December 15, 2017 (Predecessor)
(720
)
 
(69
)
 
—

 
(1
)
 
(790
)
Elimination of Predecessor Company Accumulated other comprehensive loss
720

 
69

 
—

 
1

 
790

Balance as of December 15, 2017 (Predecessor)
$
—

 
$
—

 
$
—

 
$
—

 
$
—

 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Balance as of December 16, 2017 (Successor)
$
—

 
$
—

 
$
—

 
$
—

 
$
—

Other comprehensive income (loss) before reclassifications
70

 
(31
)
 
(3
)
 
—

 
36

(Provision for) benefit from income taxes
(19
)
 
—

 
1

 
—

 
(18
)
Balance as of September 30, 2018 (Successor)
$
51

 
$
(31
)
 
$
(2
)
 
$
—

 
$
18