Revenues - Contract Assets and Liabilities (Details) - USD ($) $ in Millions	1 Months Ended	11 Months Ended
Dec. 31, 2019	Dec. 13, 2019
Contract Assets
Balance at January 1, 2018	$ 3	$ 4
Increase due to revenue recognized during the period but contingent on future performance		9
Transferred to receivables from contract assets recognized at the beginning of the period		(2)
Fresh Start Accounting Adjustments		(29)
Balance at September 30, 2018	3	3
contract with customer, asset, transferred to receivables for revenue recognized during the period		8
Contract with Customer, Asset, Cumulative Catch-up Adjustment to Revenue, Change in Estimate of Transaction Price		0
Contract Liabilities
Balance at January 1, 2018	4	64
Revenue recognized that was included in the deferred revenue balance at the beginning of the period		(61)
Increase due to cash received, excluding amount recognized as revenue during the period	8	21
Contract with Customer, Liability, Cumulative Catch-up Adjustment to Revenue, Modification of Contract		9
Balance at September 30, 2018	$ 12	$ 4

Amount of increase (decrease) in revenue recognized for cumulative catch-up adjustment from change in estimate of transaction price which increases (decreases) right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time. Includes, but is not limited to, change in assessment of whether estimate of variable consideration is constrained.

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-Publisher FASB
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Amount of increase (decrease) in revenue recognized for cumulative catch-up adjustment from change in measure of progress which increases (decreases) right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.

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Amount, after allowance for credit loss, of right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time.

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Amount of decrease in right to consideration in exchange for good or service transferred to customer when right is conditioned on something other than passage of time from transfer to receivable due to right to consideration becoming unconditional.

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Amount of obligation to transfer good or service to customer for which consideration has been received or is receivable.

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Amount of increase (decrease) in revenue recognized for cumulative catch-up adjustment from contract modification which (increases) decreases obligation to transfer good or service to customer for which consideration from customer has been received or is due.

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Amount of increase (decrease) in obligation to transfer good or service to customer for which consideration from customer has been received or is due, from business combination.

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Amount of revenue recognized that was previously included in balance of obligation to transfer good or service to customer for which consideration from customer has been received or is due.

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Change in Contract with Customer, Liability [Roll Forward]

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- Definition

Fresh Start Accounting Adjustments

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