| Dec 31, 2020 | Dec 31, 2021 | Dec 31, 2022 | Dec 31, 2023 | Dec 31, 2024 |
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| Cash and cash equivalents | 496,471 | 372 | 250 | 358 | 343 |
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| Receivables, net | - | 515 | 678 | 698 | 471 |
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| Other current assets | - | 302 | 379 | 319 | 214 |
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| Fiduciary assets | - | 1,280 | 1,509 | 1,401 | 239 |
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| Total Current Assets | 722,218 | 2,469 | 2,816 | 2,776 | 1,267 |
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| Goodwill | - | 3,638 | 3,679 | 3,543 | 3,212 |
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| Intangible assets, net | - | 4,170 | 3,872 | 3,554 | 2,855 |
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| Fixed assets, net | - | 62 | 46 | 21 | 396 |
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| Deferred tax assets, net | - | 3 | 6 | 41 | 41 |
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| Other assets | - | 472 | 542 | 497 | 422 |
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| Total Assets | 1,037 | 10,988 | 11,235 | 10,782 | 8,193 |
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| Accounts payable and accrued liabilities | - | 406 | 508 | 444 | 355 |
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| Long-Term Debt, Current Maturities | - | 38 | 31 | 25 | 25 |
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| Other current liabilities | - | 401 | 300 | 317 | 273 |
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| Fiduciary liabilities | - | 1,280 | 1,509 | 1,401 | 239 |
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| Total Current Liabilities | 3 | 2,125 | 2,348 | 2,187 | 892 |
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| Deferred tax liabilities | - | 36 | 60 | 32 | 22 |
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| Long-term debt, net | - | 2,830 | 2,792 | 2,769 | 2,000 |
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| Long-term tax receivable agreement | - | - | 568 | 733 | 757 |
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| Financial instruments | - | 135 | 97 | 109 | 51 |
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| Other liabilities | - | 353 | 281 | 210 | 158 |
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| Total Liabilities | 39 | 6,060 | 6,146 | 6,040 | 3,880 |
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| Class A Common Stock | 428 | - | - | - | - |
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| Class B Common Stock | 2,588 | - | - | - | - |
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| Treasury stock, at cost (28.8 and 6.4 shares at December 31, 2024 and December 31, 2023, respectively) | - | - | 12 | 52 | 219 |
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| Additional paid-in-capital | 8 | 4,228 | 4,514 | 4,946 | 5,141 |
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| Retained deficit | -2,556,540 | -96 | -158 | -503 | -660 |
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| Accumulated other comprehensive income | - | 8 | 95 | 71 | 47 |
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| Class A Common Stock | 428 | - | - | - | - |
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| Class B Common Stock | 2,588 | - | - | - | - |
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| Total Alight, Inc. Stockholders' Equity | 5 | 4,928 | 5,089 | 4,742 | 4,313 |
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| Noncontrolling interest | - | 788 | 650 | 280 | 4 |
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| Total Stockholders' Equity | - | 4,928 | 5,089 | 4,742 | 4,313 |
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| Total Liabilities and Stockholders' Equity | 1,037 | 10,988 | 11,235 | 10,782 | 8,193 |
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