Unaudited Consolidated Statements of Income - USD ($) shares in Millions, $ in Millions	3 Months Ended
	Mar. 31, 2024	Mar. 31, 2023
Revenues
Net premiums earned	$ 3,422	$ 2,883
Net investment income	327	199
Net realized gains (losses)	67	17
Other underwriting income	12	10
Equity in net income (loss) of investment funds accounted for using the equity method	99	48
Other income (loss)	14	11
Total revenues	3,941	3,168
Expenses
Losses and loss adjustment expenses	1,728	1,471
Acquisition expenses	607	533
Other operating expenses	363	319
Corporate expenses	53	30
Amortization of intangible assets	21	23
Interest expense	34	32
Net foreign exchange (gains) losses	(31)	18
Total expenses	2,775	2,426
Income (loss) before income taxes and income (loss) from operating affiliates	1,166	742
Income tax (expense) benefit	(101)	(64)
Income (loss) from operating affiliates	55	39
Net income (loss)	1,120	717
Net (income) loss attributable to noncontrolling interests	0	(2)
Net income (loss) available to Arch	1,120	715
Preferred dividends	(10)	(10)
Net income (loss) available to Arch common shareholders	$ 1,110	$ 705
Net income per common share and common share equivalent
Basic (per share)	$ 2.99	$ 1.92
Diluted (per share)	$ 2.92	$ 1.87
Weighted average common shares and common share equivalents outstanding
Basic (shares)	370.9	367.3
Diluted (shares)	380.5	377.6