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Income Taxes Textuals (Details) $ in Millions |  | 3 Months Ended | 9 Months Ended | 12 Months Ended |
--- | --- | --- | --- | --- | ---
Apr. 01, 2017 USD ($) | Apr. 01, 2017 USD ($) | Dec. 31, 2017 USD ($) | Dec. 31, 2018 USD ($) | Dec. 31, 2017 USD ($) | Dec. 31, 2016 USD ($) | Dec. 31, 2015 USD ($) | Dec. 22, 2017
Scenario, Forecast |  |  |  |  |  |  |  |
Investments, Owned, Federal Income Tax Note [Line Items] |  |  |  |  |  |  |  |
Alternative Minimum Tax Refund |  |  |  | $ 6.4 |  |  |  |
Predecessor |  |  |  |  |  |  |  |
Investments, Owned, Federal Income Tax Note [Line Items] |  |  |  |  |  |  |  |
Cancellation of Debt Income | $ 8,500.0 |  |  |  |  |  |  |
Effective Income Tax Rate Reconciliation, Change in Enacted Tax Rate, Amount |  | $ 0.0 | $ 473.5 |  |  | $ 0.0 | $ 0.0 |
Unrecognized Tax Benefits, Interest on Income Taxes Expense |  | 2.1 |  |  |  | 0.4 | 2.1 |
Operating Loss Carryforward |  |  |  |  |  | 4,600.0 |  |
Deferred Income Taxes and Tax Credits |  | (262.3) |  |  |  | (97.0) | (138.3) |
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount |  | (5.2) |  |  |  | (7.5) | 3.9 |
Net Unrecognized Tax Benefit |  |  |  |  |  | 20.1 |  |
Unrecognized Tax Benefits, Interest on Income Taxes Accrued |  |  |  |  |  | 5.0 | 2.4 |
Income Tax (Benefit) Expense |  | (263.8) |  |  |  | $ (94.5) | $ (207.1) |
Predecessor | Third-party Lender [Member] |  |  |  |  |  |  |  |
Investments, Owned, Federal Income Tax Note [Line Items] |  |  |  |  |  |  |  |
Cancellation of Debt Income | 3,900.0 |  |  |  |  |  |  |
Predecessor | Related Party Lender [Member] |  |  |  |  |  |  |  |
Investments, Owned, Federal Income Tax Note [Line Items] |  |  |  |  |  |  |  |
Cancellation of Debt Income | 4,600.0 |  |  |  |  |  |  |
Successor |  |  |  |  |  |  |  |
Investments, Owned, Federal Income Tax Note [Line Items] |  |  |  |  |  |  |  |
Executive Compensation Tax Deduction |  |  | $ 0.5 |  | $ 0.5 |  |  |
IRS Budget Sequestration Reduction Rate |  |  | 0.07 |  | 0.07 |  |  |
Unrecognized Tax Benefits, Interest on Income Taxes Expense |  |  | $ 4.8 |  |  |  |  |
Change In Unreconized Tax Benefit |  |  | 7.4 |  |  |  |  |
Operating Loss Carryforwards | 3,600.0 | 3,600.0 |  |  |  |  |  |
Deferred Income Taxes and Tax Credits |  |  | (99.6) |  |  |  |  |
Deferred Tax Assets, Operating Loss Carryforwards, Domestic |  |  | 3,600.0 |  | $ 3,600.0 |  |  |
Deferred Tax Assets, Operating Loss Carryforwards, State and Local |  |  | 97.0 |  | 97.0 |  |  |
Deferred Tax Assets, Tax Credit Carryforwards, Foreign | 262.0 | 262.0 | 1.6 |  | 1.6 |  |  |
Tax Basis of Investments, Gross, Unrealized Depreciation | 587.0 | 587.0 |  |  |  |  |  |
Deferred Tax Assets, Tax Credit Carryforwards, Alternative Minimum Tax | 91.3 | 91.3 | 91.3 |  | 91.3 |  |  |
Tax Adjustments, Settlements, and Unusual Provisions |  |  | 84.9 |  |  |  |  |
Deferred Tax Assets, Tax Credit Carryforwards, General Business | 97.4 | 97.4 | 97.4 |  | 97.4 |  |  |
Deferred Tax Assets, Capital Loss Carryforwards | $ 204.0 | $ 204.0 |  |  |  |  |  |
Deferred Tax Assets, Charitable Contribution Carryforwards |  |  | 2.7 |  | 2.7 |  |  |
Deferred Tax Assets, Operating Loss Carryforwards, Foreign |  |  | 1,021.3 |  | 1,021.3 |  |  |
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount |  |  | (17.3) |  | (2,400.0) |  |  |
Net Unrecognized Tax Benefit |  |  | 12.7 |  | 12.7 |  |  |
Decrease in Unrecognized Tax Benefits is Reasonably Possible |  |  | 0.5 |  | 0.5 |  |  |
Income Tax (Benefit) Expense |  |  | (161.0) |  |  |  |  |
Successor | US Deferred Tax Assets [Member] |  |  |  |  |  |  |  |
Investments, Owned, Federal Income Tax Note [Line Items] |  |  |  |  |  |  |  |
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount |  |  | (900.0) |  |  |  |  |
Successor | Australia Deferred Tax Assets [Member] |  |  |  |  |  |  |  |
Investments, Owned, Federal Income Tax Note [Line Items] |  |  |  |  |  |  |  |
Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount |  |  | (1,500.0) |  |  |  |  |
Successor | Maximum |  |  |  |  |  |  |  |
Investments, Owned, Federal Income Tax Note [Line Items] |  |  |  |  |  |  |  |
Executive Compensation Tax Deduction |  |  | 1.0 |  | 1.0 |  |  |
Operating Loss Carryforwards |  |  | 100.0 |  | 100.0 |  |  |
Deferred Tax Assets, Tax Credit Carryforwards, Foreign |  |  | 1.6 |  | $ 1.6 |  |  |
Successor | Foreign Tax Authority [Member] |  |  |  |  |  |  |  |
Investments, Owned, Federal Income Tax Note [Line Items] |  |  |  |  |  |  |  |
Deferred Income Taxes and Tax Credits |  |  | $ 260.4 |  |  |  |  |
Before Corporate Tax Rate Change [Member] | Successor |  |  |  |  |  |  |  |
Investments, Owned, Federal Income Tax Note [Line Items] |  |  |  |  |  |  |  |
Federal Corporate Tax Rate |  |  |  |  |  |  |  | 35.00%
After Corporate Tax Rate Change [Member] | Successor |  |  |  |  |  |  |  |
Investments, Owned, Federal Income Tax Note [Line Items] |  |  |  |  |  |  |  |
Federal Corporate Tax Rate |  |  |  |  |  |  |  | 21.00%

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