
	Three Months Ended March 31,
(in millions)	2024		2023
Claims and claim adjustment expense reserves at beginning of year	$	61,621	$	58,643
Less reinsurance recoverables on unpaid losses	7,817		7,790

Net reserves at beginning of year	53,804		50,853
Estimated claims and claim adjustment expenses for claims arising in the current year	6,679		6,025
Estimated decrease in claims and claim adjustment expenses for claims arising in prior years	(49)		(90)
Total increases	6,630		5,935
Claims and claim adjustment expense payments for claims arising in:
Current year	1,275		1,177
Prior years	4,435		4,382
Total payments	5,710		5,559
Unrealized foreign exchange (gain) loss	(61)		28
Net reserves at end of period	54,663		51,257
Plus reinsurance recoverables on unpaid losses	7,819		7,801
Claims and claim adjustment expense reserves at end of period	$	62,482	$	59,058

Gross claims and claim adjustment expense reserves at March 31, 2024 increased by $861 million from December 31, 2023, primarily reflecting the impacts of (i) catastrophe losses in the first three months of 2024, (ii) higher volumes of insured exposures and (iii) loss cost trends for the current accident year, partially offset by (iv) claim payments made during the first three months of 2024 and (v) net favorable prior year reserve development.

For the three months ended March 31, 2024 and 2023, estimated claims and claim adjustment expenses incurred included $49 million and $90 million, respectively, of net favorable development for claims arising in prior years, including $91 million and $105 million, respectively, of net favorable prior year reserve development, and $11 million of accretion of discount in each period.

Business Insurance. There was no net prior year reserve development in the first quarter of 2024, as better than expected loss experience in the domestic operations’ workers’ compensation product line for multiple accident years was offset primarily by higher than expected loss experience in the general liability product line for recent accident years, as well as an addition to reserves related to run-off operations. Net favorable prior year reserve development in the first quarter of 2023 totaled $19 million, primarily driven by better than expected loss experience in the domestic operations’ workers’ compensation product line for multiple accident years, partially offset by higher than expected loss experience in the general liability product line for excess coverages for multiple accident years.

Bond & Specialty Insurance. Net favorable prior year reserve development in the first quarter of 2024 totaled $24 million, primarily driven by better than expected loss experience in multiple product lines within domestic operations. Net favorable prior year reserve development in the first quarter of 2023 totaled $58 million, primarily driven by better than expected loss experience in the domestic operations’ fidelity and surety product lines and in the general liability product line for management liability coverages for recent accident years.

Personal Insurance. Net favorable prior year reserve development in the first quarter of 2024 totaled $67 million, primarily driven by better than expected loss experience in the domestic operations’ automobile product line for recent accident years. Net favorable prior year reserve development in the first quarter of 2023 totaled $28 million, primarily driven by better than expected loss experience in the domestic operations’ homeowners and other product line for recent accident years.