Long-Term Debt (Long-Term Debt) (Details) - USD ($) $ in Millions	2 Months Ended	4 Months Ended
Jun. 30, 2021	Apr. 30, 2021	Dec. 31, 2020
Successor [Member]
Debt Instrument [Line Items]
Principal debt outstanding, beginning	$ 6,794
Repayments of long term debt at matury	(4)
Principal debt outstanding, ending	6,790	$ 6,794
Unamortized fair value adjustment	232
Less: Long-term debt due within one year	(15)
Long-term debt	7,007
Amortization	$ 4
Weighted average interest rate	5.657%
Predecessor [Member]
Debt Instrument [Line Items]
Principal debt outstanding, beginning	$ 6,794	16,769
Issuance of incremental term loan		225
Issuance of Takeback Notes		750
Conversion of Unsecured Senior Notes		(10,949)
Repayments of long term subsidiary debt at matury		(1)
Principal debt outstanding, ending		6,794
Less: Unamortized debt issuance costs		(2)
Less: Unamortized premium (discount)		(39)
Less: Long-term debt due within one year		(15)	$ (5,781)
Carrying amount of debt		6,738
Fresh start accounting fair value adjustment		277
Long-term debt		7,015
Long-term debt, fair value adjustment		$ 236

Debt Instrument, Debt Less Amortized Debt Issuance Costs, Premium Discount, And Current Long Term Debt

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- Definition

Debt Instrument Unamortized Fair Value Adjustment

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- Definition

Long Term Debt Fair Value Adjustment

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- Definition

Long Term Debt, Issuance Of Incremental Term Loan

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- Definition

Long Term Debt, Issuance Of Takeback Notes

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- Definition

Repayments Of Subsidiary Debt

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Amount of noncash expense included in interest expense to amortize debt discount and premium associated with the related debt instruments. Excludes amortization of financing costs. Alternate captions include noncash interest expense.

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- Definition

The value of the financial instrument(s) that the original debt is being converted into in a noncash (or part noncash) transaction. "Part noncash" refers to that portion of the transaction not resulting in cash receipts or cash payments in the period.

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- Definition

Amount, before unamortized (discount) premium and debt issuance costs, of long-term debt. Includes, but is not limited to, notes payable, bonds payable, commercial loans, mortgage loans, convertible debt, subordinated debt and other types of debt.

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- Definition

Line items represent financial concepts included in a table. These concepts are used to disclose reportable information associated with domain members defined in one or many axes to the table.

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- Definition

Amount of debt discount to be amortized within one year or within the normal operating cycle, if longer.

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- Definition

Amount of debt premium to be amortized within one year or the normal operating cycle, if longer.

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- Definition

Weighted average interest rate of debt outstanding.

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- Definition

Total fresh-start adjustment to long-term debt.

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Amount, after unamortized (discount) premium and debt issuance costs, of long-term debt, classified as current. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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Amount after unamortized (discount) premium and debt issuance costs of long-term debt classified as noncurrent and excluding amounts to be repaid within one year or the normal operating cycle, if longer. Includes, but not limited to, notes payable, bonds payable, debentures, mortgage loans and commercial paper. Excludes capital lease obligations.

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The cash outflow during the period from the repayment of aggregate short-term and long-term debt. Excludes payment of capital lease obligations.

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