POLICY LIABILITIES

Changes in the liability for unpaid policy claims were as follows:



	Three Months Ended March 31,
(In millions)		2018			2017
Unpaid supplemental health claims, beginning of period		$	3,884		$	3,707
Less reinsurance recoverables		30			27
Net balance, beginning of period		3,854			3,680
Add claims incurred during the period related to:
Current year		1,842			1,737
Prior years		(192		)	(111		)
Total incurred		1,650			1,626
Less claims paid during the period on claims incurred during:
Current year		518			505
Prior years		1,116			1,055
Total paid		1,634			1,560
Effect of foreign exchange rate changes on unpaid claims		142			80
Net balance, end of period		4,012			3,826
Add reinsurance recoverables		31			29
Unpaid supplemental health claims, end of period		4,043			3,855
Unpaid life claims, end of period		587			375
Total liability for unpaid policy claims		$	4,630		$	4,230

The incurred claims development related to prior years reflects favorable claims experience compared to previous estimates. The favorable claims development of $192 million for the three-month period ended March 31, 2018 comprises approximately $97 million from Japan, which represents approximately 51% of the total. Excluding the impact of foreign exchange of a loss of approximately $5 million from December 31, 2017 to March 31, 2018, the favorable claims development in Japan would have been approximately $92 million, representing approximately 48% of the total.

The Company has experienced continued favorable claim trends in 2018 for its core health products in Japan. The Company's experience in Japan related to the average length of stay in the hospital for cancer treatment has shown continued decline in the current period. In addition, cancer treatment patterns in Japan are continuing to be influenced by significant advances in early-detection techniques and by the increased use of pathological diagnosis rather than clinical exams. Additionally, follow-up radiation and chemotherapy treatments are occurring more often on an outpatient basis. Such changes in treatment not only increase the quality of life and initial outcomes for the patients, but also decrease the average length of each hospital stay, resulting in favorable claims development.

The remainder of the favorable claims development related to prior years for the three-month period ended March 31, 2018, reflects Aflac U.S. favorable claims experience compared to previous estimates, primarily in the cancer and accident lines of business.