| **Stock-based Compensation Plans - Schedule of Stock Options (Details) - USD ($) $ / shares in Units, shares in Thousands, $ in Millions**                         | 12 Months Ended |         |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------|-----------------|---------|
||
| **Share-based Compensation Arrangement by Share-based Payment Award [Line Items]**                                                                                 |            |    |   |   |
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value |            | $ 10.53 | $ 14.12 |   |
| **Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding [Roll Forward]**                                                         |            |    |   |   |
| Options, Outstanding, Number                                                                                                                                       | 2,886           | 3,657   | 5,000 |   |
| Options, Grants in Period, Net of Forfeitures                                                                                                                      | 35              | 40      | 251 |   |
| Options, Exercises in Period                                                                                                                                       | 0               | (44)    | (784) |   |
| Options, Forfeitures and Expirations in Period                                                                                                                     | (86)            | (767)   | (810) |   |
| Options, Outstanding, Number                                                                                                                                       | 2,835           | 2,886   | 3,657 |   |
| Options, Exercisable, Number                                                                                                                                       | 2,695           | 2,407   | 2,637 |   |
| **Share-based Compensation Arrangement by Share-based Payment Award, Options, Outstanding, Weighted Average Exercise Price [Abstract]**                            |            |    |   |   |
| Options, Outstanding, Weighted Average Exercise Price                                                                                                              | $ 39.33         | $ 39.46 | $ 37.94 |   |
| Options, Grants in Period, Weighted Average Exercise Price                                                                                                         | 10.60           | 37.03   | 38.51 |   |
| Options, Exercises in Period, Weighted Average Exercise Price                                                                                                      | 0.00            | 25.68   | 24.33 |   |
| Options, Forfeitures and Expirations in Period, Weighted Average Exercise Price                                                                                    | 42.30           | 40.60   | 44.41 |   |
| Options, Outstanding, Weighted Average Exercise Price                                                                                                              | 38.89           | 39.33   | 39.46 |   |
| Options, Exercisable, Weighted Average Exercise Price                                                                                                              | $ 39.29         | $ 40.27 | $ 41.34 |   |
| Performance-based Stock Options [Member]                                                                                                                           |            |    |   |   |
| **Share-based Compensation Arrangement by Share-based Payment Award [Line Items]**                                                                                 |            |    |   |   |
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number                                        | 973             | 1,409   | 941 | 299 |
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value        | $ 30.47         | $ 31.64 | $ 35.41 | $ 34.47 |
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period                                         | 0               | 729     | 651 |   |
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ 0.00          | $ 27.61 | $ 35.83 |   |
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period                                      | 436             | 261     | 9 |   |
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value      | $ 34.22         | $ 33.99 | $ 35.09 |   |
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other Than Options, Exercisable, Number                                      | 0               | 0       | 0 |   |
| Market-based Stock Options [Member] [Member]                                                                                                                       |            |    |   |   |
| **Share-based Compensation Arrangement by Share-based Payment Award [Line Items]**                                                                                 |            |    |   |   |
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number                                        | 567             | 615     | 670 | 759 |
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value        | $ 27.24         | $ 27.24 | $ 27.24 | $ 27.24 |
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeited in Period                                      | 48              | 55      | 89 |   |
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Forfeitures, Weighted Average Grant Date Fair Value      | $ 27.24         | $ 27.24 | $ 27.24 |   |
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other Than Options, Exercisable, Number                                      | 567             | 0       | 0 |   |
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other Than Options, Exercisable, Weighted Average Grant Date Fair Value      | $ 27.24         | $ 0.00  | $ 0.00 |   |
| Restricted Stock [Member]                                                                                                                                          |            |    |   |   |
| **Share-based Compensation Arrangement by Share-based Payment Award [Line Items]**                                                                                 |            |    |   |   |
| Share-based Compensation Arrangement By Share-based Payment Award, Equity Instruments Other than Options, Aggregate Grant Date Fair Value                          | $ 0.1           | $ 1.1   | $ 0.1 |   |
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Number                                        | 0               | 0       | 41 | 41 |
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Nonvested, Weighted Average Grant Date Fair Value        | $ 0.00          | $ 0.00  | $ 24.13 | $ 24.13 |
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period                                         | 5               | 2       | 4 |   |
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Grants in Period, Weighted Average Grant Date Fair Value | $ 12.52         | $ 29.50 | $ 33.70 |   |
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period                                         | 5               | 43      | 4 |   |
| Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other than Options, Vested in Period, Weighted Average Grant Date Fair Value | $ 12.52         | $ 24.38 | $ 33.70 |   |

| X                                                                                                                                                                                                                                                                                                                                                                                                                                                   |
|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Share-based Compensation Arrangement By Share-based Payment Award, Equity Instruments Other than Options, Aggregate Grant Date Fair Value
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Share-based Compensation Arrangement by Share-based Payment Award, Equity Instruments Other Than Options, Exercisable, Number
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The number of equity-based payment instruments, excluding stock (or unit) options, that were forfeited during the reporting period.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Weighted average fair value as of the grant date of equity-based award plans other than stock (unit) option plans that were not exercised or put into effect as a result of the occurrence of a terminating event.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                  |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The number of grants made during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).
+ References
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The weighted average fair value at grant date for nonvested equity-based awards issued during the period on other than stock (or unit) option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, performance target plan).
+ References
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The number of non-vested equity-based payment instruments, excluding stock (or unit) options, that validly exist and are outstanding as of the balance sheet date.
+ References
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The weighted average fair value of nonvested awards on equity-based plans excluding option plans (for example, phantom stock or unit plan, stock or unit appreciation rights plan, revenue or profit achievement stock award plan) for which the employer is contingently obligated to issue equity instruments or transfer assets to an employee who has not yet satisfied service or performance criteria necessary to gain title to proceeds from the sale of the award or underlying shares or units.
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|-----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The number of equity-based payment instruments, excluding stock (or unit) options, that vested during the reporting period.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             |
|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The weighted average fair value as of grant date pertaining to an equity-based award plan other than a stock (or unit) option plan for which the grantee gained the right during the reporting period, by satisfying service and performance requirements, to receive or retain shares or units, other instruments, or cash in accordance with the terms of the arrangement.
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                          |
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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
The number of shares into which fully or partially vested stock options outstanding as of the balance sheet date can be currently converted under the option plan.
+ References
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|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
The weighted-average price as of the balance sheet date at which grantees can acquire the shares reserved for issuance on vested portions of options outstanding and currently exercisable under the stock option plan.
+ References
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| - Definition
For presentations that combine terminations, the number of shares under options that were cancelled during the reporting period as a result of occurrence of a terminating event specified in contractual agreements pertaining to the stock option plan or that expired.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                |
|--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Weighted average price of options that were either forfeited or expired.
+ References
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| X                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
|----------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Net number of share options (or share units) granted during the period.
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Number of options outstanding, including both vested and non-vested options.
+ References
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| - Definition
A roll forward is a reconciliation of a concept from the beginning of a period to the end of a period.
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No definition available.
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Weighted average price at which grantees can acquire the shares reserved for issuance under the stock option plan.
+ References
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| - References
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| - Definition
Weighted average price at which option holders acquired shares when converting their stock options into shares.
+ References
No definition available.
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|-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Weighted average per share amount at which grantees can acquire shares of common stock by exercise of options.
+ References
No definition available.
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|---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
| - Definition
Number of share options (or share units) exercised during the current period.
+ References
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