| **Postretirement Benefits - Narrative (Details) employees in Thousands, $ in Millions**                     | 1 Months Ended | 3 Months Ended | 9 Months Ended | 12 Months Ended |
|-------------------------------------------------------------------------------------------------------------|----------------|----------------|----------------|-----------------|
||
| **Defined Benefit Plan Disclosure [Line Items]**                                                            |           |           |           |            |   |   |   |
| Number Of Former Employees And Their Beneficiaries Included In Retiree Population | employees               |           |           |           |            | 35 |   |   |
| Defined Benefit Plan, Benefit Obligation, Period Increase (Decrease)                                        |           |           | $ 33           |            |   |   |   |
| Defined benefit plan, weighted average rate of increase in in per capita cost percent of benefit obligation |           |           |           |            | 7.80% |   |   |
| Restructuring Charges                                                                                       |           |           |           |            | $ 76 | $ 42 | $ 25 |
| Defined Benefit Plan, Accumulated Benefit Obligation                                                        |           |           |           |            | 4,000 | 4,000 |   |
| Defined Benefit Plan, Curtailments                                                                          |           |           | 4              |            |   |   |   |
| Defined Contribution Plan, Cost Recognized                                                                  |           |           |           |            | 29 | 27 | 27 |
| Defined Benefit Plans, Estimated Future Employer Contributions in Current Fiscal Year                       |           |           |           |            | 100 |   |   |
| United States Postretirement Benefit Plan of US Entity [Member]                                             |           |           |           |            |   |   |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                            |           |           |           |            |   |   |   |
| Deferred Income Taxes and Other Assets, Noncurrent                                                          |           |           |           |            | 533 |   |   |
| Pension Benefits                                                                                            |           |           |           |            |   |   |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                            |           |           |           |            |   |   |   |
| Defined Benefit Plan, Contributions by Plan Participants                                                    |           |           |           |            | 0 | 0 |   |
| Employer contributions                                                                                      |           |           |           |            | $ 113 | $ 164 |   |
| Discount rate used to calculate benefit obligation                                                          |           |           |           |            | 4.00% | 3.70% |   |
| Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax   |           |           |           |            | $ 214 | $ 71 | (585) |
| Defined Benefit Plan, Curtailments                                                                          |           |           |           |            | 0 | 2 |   |
| Defined Benefit Plan, Benefits Paid                                                                         |           |           |           |            | 309 | 318 |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                             |           |           | 2,519          |            | 2,422 | 2,627 | 2,519 |
| Other Postretirement Benefit Plan [Member]                                                                  |           |           |           |            |   |   |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                            |           |           |           |            |   |   |   |
| Defined Benefit Plan, Contributions by Plan Participants                                                    |           |           |           |            | $ 31 | 40 |   |
| Defined benefit plan, weighted average rate of increase in in per capita cost percent of benefit obligation |           |           |           |            | 91.00% |   |   |
| Defined Benefit Plan, Ultimate Health Care Cost Trend Rate                                                  |           |           |           |            | 5.00% |   |   |
| Defined Benefit Plan, Health Care Cost Trend Rate Assumed for Next Fiscal Year                              |           |           |           |            | 8.20% |   |   |
| Employer contributions                                                                                      |           |           |           |            | $ 2 | $ 2 |   |
| Discount rate used to calculate benefit obligation                                                          |           |           |           |            | 4.10% | 3.70% |   |
| Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax   |           |           |           |            | $ (42) | $ 314 | (200) |
| Defined Benefit Plan, Curtailments                                                                          |           |           |           |            | 0 | 0 |   |
| Defined Benefit Plans, Estimated Future Employer Contributions in Next Fiscal Year                          |           |           |           |            | 2 |   |   |
| Defined Benefit Plan, Benefits Paid                                                                         |           |           |           |            | 183 | 185 |   |
| Defined benefit plan, benefits paid from Company assets                                                     |           |           |           |            | 61 | 51 |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                             |           |           | $ 447          |            | 369 | 415 | $ 447 |
| Unfunded pension plan [Member]                                                                              |           |           |           |            |   |   |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                            |           |           |           |            |   |   |   |
| Defined Benefit Plan, Benefits Paid                                                                         |           |           |           |            | $ 15 | 14 |   |
| Effect Of Remeasurement On Plan [Member]                                                                    |           |           |           |            |   |   |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                            |           |           |           |            |   |   |   |
| Other Comprehensive (Income) Loss, Pension and Other Postretirement Benefit Plans, Adjustment, Net of Tax   |           |           |           | $ 10            |   |   |   |
| Facility Closing [Member] | Chatham [Member] | Other Postretirement Benefit Plan [Member]                   |           |           |           |            |   |   |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                            |           |           |           |            |   |   |   |
| Restructuring charges                                                                                       |           | $ 14           |           |            |   |   |   |
| Discount rate used to calculate benefit obligation                                                          |           | 3.80%          | 4.10%          | 3.80%           |   |   | 4.10% |
| Designated as Hedging Instrument [Member] | Put Option [Member]                                             |           |           |           |            |   |   |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                            |           |           |           |            |   |   |   |
| Derivative, Term of Contract                                                                                | 3 years        |           |           |            |   |   |   |
| Fixed Income Investments [Member]                                                                           |           |           |           |            |   |   |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                            |           |           |           |            |   |   |   |
| Defined Benefit Plan, Target Plan Asset Allocations                                                         |           |           |           |            | 30.00% |   |   |
| Other Investments [Member]                                                                                  |           |           |           |            |   |   |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                            |           |           |           |            |   |   |   |
| Defined Benefit Plan, Target Plan Asset Allocations                                                         |           |           |           |            | 10.00% |   |   |
| Cash [Member]                                                                                               |           |           |           |            |   |   |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                            |           |           |           |            |   |   |   |
| Defined Benefit Plan, Target Plan Asset Allocations                                                         |           |           |           |            | 5.00% |   |   |
| US Large Cap [Member]                                                                                       |           |           |           |            |   |   |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                            |           |           |           |            |   |   |   |
| Defined Benefit Plan, Target Plan Asset Allocations                                                         |           |           |           |            | 15.00% |   |   |
| US Large Cap [Member] | Pension Benefits                                                                    |           |           |           |            |   |   |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                            |           |           |           |            |   |   |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                             |           |           |           |            | $ 209 | 227 |   |
| US Large Cap [Member] | Other Postretirement Benefit Plan [Member]                                          |           |           |           |            |   |   |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                            |           |           |           |            |   |   |   |
| Defined Benefit Plan, Fair Value of Plan Assets                                                             |           |           |           |            | $ 25 | $ 28 |   |
| Equity Method Investments [Member]                                                                          |           |           |           |            |   |   |   |
| **Defined Benefit Plan Disclosure [Line Items]**                                                            |           |           |           |            |   |   |   |
| Defined Benefit Plan, Target Plan Asset Allocations                                                         |           |           |           |            | 55.00% |   |   |

| X                                                                                                                                                                                                                                                                                           |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Defined benefit plan, benefits paid from Company assets
+ References
No definition available.
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| - Definition
Defined benefit plan, weighted average rate of increase in in per capita cost percent of benefit obligation
+ References
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| X                                                                                                                                                                                                                                                                                                                                         |
|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Number Of Former Employees And Their Beneficiaries Included In Retiree Population
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| - Definition
Amount after allocation of valuation allowances of deferred tax asset attributable to deductible temporary differences and other assets expected to be realized or consumed after one year or normal operating cycle, if longer.
+ References
No definition available.
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
For defined benefit pension plans, the actuarial present value of benefits (whether vested or nonvested) attributed by the pension benefit formula to employee service rendered before a specified date and based on employee service and compensation (if applicable) before that date. The accumulated benefit obligation differs from the projected benefit obligation in that it includes no assumption about future compensation levels. For plans with flat-benefit or nonpay-related pension benefit formulas, the accumulated benefit obligation and the projected benefit obligation are the same.
+ References
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|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The interest rate used to adjust for the time value of money for the plan.
+ References
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Net increase or decrease in the plan benefit obligation during the reporting period.
+ References
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of payments made for which participants are entitled under a pension plan, including pension benefits, death benefits, and benefits due on termination of employment. Also includes payments made under a postretirement benefit plan, including prescription drug benefits, health care benefits, life insurance benefits, and legal, educational and advisory services. This item represents a periodic decrease to the plan obligations and a decrease to plan assets.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The increase in the fair value of plan assets from contributions made by the employer.
+ References
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|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of contributions made by plan participants. This item represents a periodic increase to the plan obligation and an increase to plan assets.
+ References
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The amount of decrease that is related to an event that significantly reduces the expected years of future service of present employees or eliminates for a significant number of employees the accrual of defined benefits for some or all of their future services.
+ References
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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.
+ References
No definition available.
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|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Assets, usually stocks, bonds, and other investments, that have been segregated and restricted (usually in a trust) to provide benefits, at their fair value as of the measurement date. Plan assets include amounts contributed by the employer (and by employees for a contributory plan) and amounts earned from investing the contributions, less benefits paid. If a plan has liabilities other than for benefits, those non-benefit obligations may be considered as reductions of plan assets.
+ References
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|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The assumed health care cost trend rate for the next year used to measure the expected cost of benefits covered by the plan (gross eligible charges). This is based upon the annual rate of change in the cost of health care benefits currently provided by the postretirement benefit plan, due to factors other than changes in the composition of the plan population by age and dependency status.
+ References
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Target allocation of investments of this type to total plan assets presented on a weighted average basis.
+ References
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|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The ultimate trend rate for health care costs.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                  |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of employer's best estimate of contributions expected to be paid to the plan in the current remaining fiscal period.
+ References
No definition available.
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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of employer's best estimate of contributions expected to be paid to the plan during the next fiscal year beginning after the date of the latest statement of financial position.
+ References
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| - Definition
The amount of the cost recognized during the period for defined contribution plans.
+ References
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| - Definition
Period the derivative contract is outstanding, in 'PnYnMnDTnHnMnS' format, for example, 'P1Y5M13D' represents the reported fact of one year, five months, and thirteen days.
+ References
No definition available.
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|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount before tax, after reclassification adjustments, of (increase) decrease in accumulated other comprehensive (income) loss related to pension and other postretirement defined benefit plans.
+ References
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| X                                                                                                                                                                                                                                                                                  |
|------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Period expense related to postemployment benefits.
+ References
No definition available.
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Amount of expenses associated with exit or disposal activities pursuant to an authorized plan. Excludes expenses related to a discontinued operation or an asset retirement obligation.
+ References
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