Medical Costs Payable (Notes)

12 Months Ended

Dec. 31, 2018

Medical Costs Payable

Medical Costs Payable

The following table shows the components of the change in medical costs payable for the years ended December 31:

(in millions)	2018			2017			2016
Medical costs payable, beginning of period	$	17,871		$	16,391		$	14,330
Acquisitions	339			83			—
Reported medical costs:
Current year	145,723			130,726			117,258
Prior years	(320		)	(690		)	(220		)
Total reported medical costs	145,403			130,036			117,038
Medical payments:
Payments for current year	(127,155		)	(113,811		)	(101,696		)
Payments for prior years	(16,567		)	(14,828		)	(13,281		)
Total medical payments	(143,722		)	(128,639		)	(114,977		)
Medical costs payable, end of period	$	19,891		$	17,871		$	16,391

For the years ended December 31, 2018 and 2016, no individual factors significantly impacted medical cost reserve development. For the year ended December 31, 2017, medical cost reserve development was primarily driven by lower than expected health system utilization levels.

Medical costs payable included IBNR of $13.2 billion and $12.3 billion at December 31, 2018 and 2017, respectively. Substantially all of the IBNR balance as of December 31, 2018 relates to the current year. The following is information about incurred and paid medical cost development as of December 31, 2018:

	Net Incurred Medical Costs
(in millions)	For the Years ended December 31,
Year	2017			2018
2017	$	130,726		$	130,441
2018				145,723
Total				$	276,164
	Net Cumulative Medical Payments
(in millions)	For the Years ended December 31,
Year	2017			2018
2017	$	(113,811	)	$	(129,778	)
2018				(127,155		)
Total				(256,933		)
Net remaining outstanding liabilities prior to 2017				660
Total medical costs payable				$	19,891