| **Income Taxes - Narrative (Details) - USD ($) $ in Millions**       | 3 Months Ended | 12 Months Ended |
|----------------------------------------------------------------------|----------------|-----------------|
||
| **Operating Loss Carryforwards [Line Items]**                        |           |            |   |   |   |
| Income Tax Expense (Benefit)                                         |           |            | $ 51 | $ 26 | $ (171) |
| Valuation Allowance, Deferred Tax Asset, Increase (Decrease), Amount | $ (16)         | $ 29            | 41 | 234 | 350 |
| Deferred Tax Assets, Valuation Allowance                             | 3,174          |            | 3,260 | 3,174 |   |
| Undistributed Earnings of Foreign Subsidiaries                       |           |            | 565 |   |   |
| Deferred tax liabilities related to unremitted foreign earnings      | 6              |            | 37 | 6 |   |
| Deferred Tax Assets, Operating Loss Carryforwards, Domestic          |           |            | 840 |   |   |
| Deferred Tax Assets, Operating Loss Carryforwards, State and Local   |           |            | 145 |   |   |
| Deferred Tax Assets, Operating Loss Carryforwards, Foreign           |           |            | 176 |   |   |
| Deferred Tax Assets, Operating Loss Carryforwards                    | 1,213          |            | $ 1,161 | 1,213 |   |
| Income Taxes Percent Likelihood Of Being Realized Upon Settlement    |           |            | 50.00% |   |   |
| Unrecognized Tax Benefits                                            | 47             |            | $ 41 | 47 |   |
| Unrecognized Tax Benefits, Income Tax Penalties and Interest Expense |           |            | (1) | 4 | (6) |
| Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued | $ 8            |            | 8 | $ 8 |   |
| Intraperiod Tax Allocation Rule [Member]                             |           |            |   |   |   |
| **Operating Loss Carryforwards [Line Items]**                        |           |            |   |   |   |
| Income Tax Expense (Benefit)                                         |           |            |   |   | (220) |
| Other Comprehensive Income (Loss) [Member]                           |           |            |   |   |   |
| **Operating Loss Carryforwards [Line Items]**                        |           |            |   |   |   |
| Income Tax Expense (Benefit)                                         |           |            | $ (14) |   | (212) |
| Additional Paid-in Capital [Member]                                  |           |            |   |   |   |
| **Operating Loss Carryforwards [Line Items]**                        |           |            |   |   |   |
| Income Tax Expense (Benefit)                                         |           |            |   |   | $ (8) |
| Convertible Subordinated Debt [Member]                               |           |            |   |   |   |
| **Operating Loss Carryforwards [Line Items]**                        |           |            |   |   |   |
| Income Tax Expense (Benefit)                                         |           | $ (13)          |   |   |   |
| Maximum [Member]                                                     |           |            |   |   |   |
| **Operating Loss Carryforwards [Line Items]**                        |           |            |   |   |   |
| Operating Loss Carryforwards, Duration of Carryforward               |           |            | 20 years |   |   |
| Minimum [Member]                                                     |           |            |   |   |   |
| **Operating Loss Carryforwards [Line Items]**                        |           |            |   |   |   |
| Operating Loss Carryforwards, Duration of Carryforward               |           |            | 5 years |   |   |
| Stock Option Tax Benefits [Member]                                   |           |            |   |   |   |
| **Operating Loss Carryforwards [Line Items]**                        |           |            |   |   |   |
| Deferred Tax Assets, Operating Loss Carryforwards                    |           |            | $ 63 |   |   |

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Income Taxes Percent Likelihood Of Being Realized Upon Settlement
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| - Definition
Amount before allocation of valuation allowances of deferred tax asset attributable to deductible operating loss carryforwards.
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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible domestic operating loss carryforwards. Excludes state and local operating loss carryforwards.
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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible foreign operating loss carryforwards.
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Amount before allocation of valuation allowances of deferred tax asset attributable to deductible state and local operating loss carryforwards.
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Amount of deferred tax assets for which it is more likely than not that a tax benefit will not be realized.
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Amount of deferred tax liability attributable to taxable temporary differences from undistributed earnings of subsidiaries and other recognized entities not within the country of domicile of the entity.
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Amount of current income tax expense (benefit) and deferred income tax expense (benefit) pertaining to continuing operations.
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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 undistributed earnings of foreign subsidiaries intended to be permanently reinvested outside the country of domicile.
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Amount of unrecognized tax benefits pertaining to uncertain tax positions taken in tax returns.
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Amount accrued for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.
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Amount of expense for interest on an underpayment of income taxes and penalties related to a tax position claimed or expected to be claimed in the tax return.
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Amount of increase (decrease) in the valuation allowance for a specified deferred tax asset.
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