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Business Combinations - Summary of Unaudited Pro Forma Historical Results (Detail) - USD ($) $ / shares in Units, $ in Millions | 12 Months Ended
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Dec. 31, 2020 | Dec. 31, 2019
Business Combinations [Abstract] |  |
Total revenues | $ 7,108.7 | $ 7,352.7
Net earnings attributable to controlling interests | $ 817.6 | $ 670.5
Basic net earnings per share | $ 4.26 | $ 3.57
Diluted net earnings per share | $ 4.17 | $ 3.49

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