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Employee Share-Based Incentive Compensation Plans - Performance Shares Granted (Details) - Performance Shares - USD ($) $ in Millions | Dec. 31, 2022 | Dec. 31, 2021 | Dec. 31, 2020 | Dec. 31, 2019
--- | --- | --- | --- | ---
Share-based compensation arrangement by share-based payment award |  |  |  |
Number of nonvested options before forfeitures (in shares) | 40,050 |  |  |
Incentive compensation payable before forfeitures | $ 68.5 |  |  |
Assumed forfeitures (in shares) | (601) |  |  |
Assumed forfeitures | $ (1.0) |  |  |
Shares outstanding (in shares) | 39,449 | 40,828 | 42,458 | 42,473
Accrued incentive compensation | $ 67.5 | $ 42.2 | $ 56.3 | $ 43.7
2022 – 2024 |  |  |  |
Share-based compensation arrangement by share-based payment award |  |  |  |
Number of nonvested options before forfeitures (in shares) | 13,225 |  |  |
Incentive compensation payable before forfeitures | $ 11.0 |  |  |
2021 – 2023 |  |  |  |
Share-based compensation arrangement by share-based payment award |  |  |  |
Number of nonvested options before forfeitures (in shares) | 13,475 |  |  |
Incentive compensation payable before forfeitures | $ 19.7 |  |  |
2020 – 2022 |  |  |  |
Share-based compensation arrangement by share-based payment award |  |  |  |
Number of nonvested options before forfeitures (in shares) | 13,350 |  |  |
Incentive compensation payable before forfeitures | $ 37.8 |  |  |

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- Definition Aggregate carrying value as of the balance sheet date of liabilities for incentive compensation arrangements. + References No definition available. + Details
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- Definition This element represents the number of non-vested performance shares before forfeiture assumptions. + References No definition available. + Details
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