Business Combinations - Unaudited Pro Forma Results (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended
	Dec. 31, 2022	Dec. 31, 2021	Dec. 31, 2020
Two Thousand Twenty Two Acquisition
Business Acquisition Pro Forma Information Nonrecurring Adjustment [Line Items]
Total revenues	$ 3,789.8	$ 3,514.1
Income before income taxes	891.4	776.2
Net income	$ 683.5	$ 597.4
Net income per share:
Basic	$ 2.42	$ 2.11
Diluted	$ 2.41	$ 2.10
Weighted average number of shares outstanding:
Basic	277,646	276,276
Diluted	278,783	277,667
Two Thousand Twenty One Acquisition
Business Acquisition Pro Forma Information Nonrecurring Adjustment [Line Items]
Total revenues		$ 3,128.5	$ 2,751.2
Income before income taxes		779.5	653.3
Net income		$ 600.0	$ 502.9
Net income per share:
Basic		$ 2.13	$ 1.78
Diluted		$ 2.12	$ 1.77
Weighted average number of shares outstanding:
Basic		276,024	274,334
Diluted		277,414	275,867
Two Thousand Twenty Acquisition
Business Acquisition Pro Forma Information Nonrecurring Adjustment [Line Items]
Total revenues			$ 2,714.3
Income before income taxes			650.6
Net income			$ 500.9
Net income per share:
Basic			$ 1.77
Diluted			$ 1.76
Weighted average number of shares outstanding:
Basic			274,334
Diluted			275,867