Retroactive reinsurance policies provide indemnification of losses and loss adjustment expenses of short-duration insurance contracts with respect to underlying loss events that occurred prior to the contract inception date. Claims payments may commence immediately after the contract inception date or, when applicable, once a contractual retention amount has been reached. Reconciliations of the changes in estimated liabilities for retroactive reinsurance unpaid losses and loss adjustment expenses (“claim liabilities”) and related deferred charge reinsurance assumed assets for each of the nine months ending September 30, 2020 and 2019 follow (in millions).

	2020						2019
	Unpaid losses and loss adjustment expenses			Deferred charges reinsurance assumed			Unpaid losses and loss adjustment expenses			Deferred charges reinsurance assumed
Balances at beginning of year	$	42,441		$	(13,747	)	$	41,834		$	(14,104	)
Incurred losses and loss adjustment expenses:
Current year contracts		—			—			175			(82	)
Prior years’ contracts		131			735			(2	)		827
Total		131			735			173			745
Paid losses and loss adjustment expenses		(786	)		—			(643	)		—
Balances at September 30	$	41,786		$	(13,012	)	$	41,364		$	(13,359	)
Incurred losses and loss adjustment expenses, net of deferred charges	$	866					$	918

In the preceding table, classifications of incurred losses and loss adjustment expenses are based on the inception dates of the contracts. Incurred losses and loss adjustment expenses in the first nine months related to contracts written in prior years were $866 million in 2020 and $825 million in 2019. Such losses reflected the recurring amortization of deferred charges and the effects of changes in the estimated timing and amount of future loss payments.

Berkshire’s subsidiary, National Indemnity Company (“NICO”), is party to a contract with various subsidiaries of American International Group, Inc. (collectively, “AIG”), in which NICO’s ultimate liability is contractually limited to $20 billion. Our estimated ultimate claim liabilities with respect to the AIG contract at both September 30, 2020 and December 31, 2019 were $18.2 billion. Deferred charge assets related to the AIG contract were approximately $5.8 billion at September 30, 2020 and $6.3 billion at December 31, 2019.