
(Dollars in millions)	Three months ended June 30,				Six months ended June 30,
	2025		2024		2025		2024
Gross loss and loss expense reserves, beginning of period	$	10,707	$	9,178	$	9,937	$	8,975
Less reinsurance recoverable	551		332		269		362
Net loss and loss expense reserves, beginning of period	10,156		8,846		9,668		8,613





Net incurred loss and loss expenses related to:
Current accident year	1,650		1,452		3,628		2,822
Prior accident years	(63)		(40)		(154)		(140)
Total incurred	1,587		1,412		3,474		2,682
Net paid loss and loss expenses related to:
Current accident year	591		483		1,184		688
Prior accident years	655		584		1,461		1,416
Total paid	1,246		1,067		2,645		2,104
Net loss and loss expense reserves, end of period	10,497		9,191		10,497		9,191
Plus reinsurance recoverable	504		303		504		303
Gross loss and loss expense reserves, end of period	$	11,001	$	9,494	$	11,001	$	9,494

We use actuarial methods, models and judgment to estimate, as of a financial statement date, the property casualty loss and loss expense reserves required to pay for and settle all outstanding insured claims, including incurred but not reported (IBNR) claims, as of that date. The actuarial estimate is subject to review and adjustment by an inter-departmental committee that includes actuarial, claims, underwriting, loss prevention and accounting management. This committee is familiar with relevant company and industry business, claims and underwriting trends, as well as general economic and legal trends that could affect future loss and loss expense payments. The amount we will actually have to pay for claims can be highly uncertain. This uncertainty, together with the size of our reserves, makes the loss and loss expense reserves our most significant estimate. The reserve for loss and loss expenses in the condensed consolidated balance sheets also included $71 million and $61 million at June 30, 2025, and 2024, respectively, for certain life and health loss and loss expense reserves.

We experienced $63 million of favorable development on prior accident years, including $42 million of favorable development in commercial lines, $19 million of favorable development in personal lines and $5 million of favorable development in excess and surplus lines for the three months ended June 30, 2025. Within commercial lines, we recognized favorable reserve development of $40 million for the commercial property line and $17 million for the workers' compensation line due to reduced uncertainty of prior accident year loss and loss adjustment expense for these lines. This was partially offset by unfavorable reserve development of $18 million for the commercial auto line. Within personal lines, we recognized favorable reserve development of $25 million for the homeowner line.

We experienced $154 million of favorable development on prior accident years, including $85 million of favorable development in commercial lines, $38 million of favorable development in personal lines and $14 million of favorable development in excess and surplus lines for the six months ended June 30, 2025. Within commercial lines, we recognized favorable reserve development of $75 million for the commercial property line and $28 million for the workers' compensation line due to reduced uncertainty of prior accident year loss and loss adjustment expense for these lines. This was partially offset by unfavorable reserve development of $24 million for the commercial auto line. Within personal lines, we recognized favorable reserve development of $44 million for the homeowner line.

We experienced $40 million of favorable development on prior accident years, including $29 million of favorable development in commercial lines, $6 million of unfavorable development in personal lines and $3 million of unfavorable development in excess and surplus lines for the three months ended June 30, 2024. Within commercial lines, we recognized favorable reserve development of $28 million for the workers' compensation line and $21 million for the commercial property line due to reduced uncertainty of prior accident year loss and loss adjustment expense for these lines. This was partially offset by unfavorable reserve development of $28 million for the commercial casualty line. Within personal lines, we recognized unfavorable reserve development of $12 million for the personal auto line.