Segment Information

The results of our operations are described through three reportable segments: Commercial & Specialty Business, Government Business and Other, as further described in Note 19, “Segment Information,” to our audited consolidated financial statements as of and for the year ended December 31, 2017 included in our 2017 Annual Report on Form 10-K.

Financial data by reportable segment for the three and nine months ended September 30, 2018 and 2017 is as follows:



	Commercial & Specialty Business		Government Business		Other			Total
Three Months Ended September 30, 2018
Operating revenue	$	9,128	$	13,841	$	11		$	22,980
Operating gain (loss)	833		466		(50		)	1,249
Three Months Ended September 30, 2017
Operating revenue	$	10,052	$	12,037	$	8		$	22,097
Operating gain (loss)	535		457		(10		)	982
Nine Months Ended September 30, 2018
Operating revenue	$	27,357	$	40,647	$	33		$	68,037
Operating gain (loss)	3,295		1,494		(113		)	4,676
Nine Months Ended September 30, 2017
Operating revenue	$	30,651	$	35,946	$	17		$	66,614
Operating gain (loss)	2,805		1,069		(80		)	3,794

The major product revenues for each of the reportable segments for the three and nine months ended September 30, 2018 and 2017 are as follows:



	Three Months Ended September 30				Nine Months Ended September 30
	2018		2017		2018		2017
Commercial & Specialty Business
Managed care products	$	7,377	$	8,478	$	22,212	$	25,815
Managed care services	1,334		1,196		3,918		3,651
Dental/Vision products and services	306		305		914		913
Other	111		73		313		272
Total Commercial & Specialty Business	9,128		10,052		27,357		30,651
Government Business
Managed care products	13,695		11,934		40,276		35,619
Managed care services	146		103		371		327
Total Government Business	13,841		12,037		40,647		35,946
Other
Other	11		8		33		17
Total product revenues	$	22,980	$	22,097	$	68,037	$	66,614

The classification between managed care products and managed care services in the above table primarily distinguishes between the levels of risk assumed. Managed care products represent insurance products where we bear the insurance risk, whereas managed care services represent product offerings where we provide claims adjudication and other administrative services to the customer, but the customer principally bears the insurance risk.

A reconciliation of reportable segments’ operating revenues to the amounts of total revenues included in our consolidated statements of income for the three and nine months ended September 30, 2018 and 2017 is as follows:



	Three Months Ended September 30						Nine Months Ended September 30
	2018			2017			2018			2017
Reportable segments’ operating revenues	$	22,980		$	22,097		$	68,037		$	66,614
Net investment income	250			220			708			628
Net realized gains on financial instruments	27			115			5			138
Other-than-temporary impairment losses recognized in income	(6		)	(6		)	(18		)	(21		)
Total revenues	$	23,251		$	22,426		$	68,732		$	67,359

A reconciliation of reportable segments’ operating gain to income before income tax expense included in our consolidated statements of income for the three and nine months ended September 30, 2018 and 2017 is as follows:



	Three Months Ended September 30						Nine Months Ended September 30
	2018			2017			2018			2017
Reportable segments’ operating gain	$	1,249		$	982		$	4,676		$	3,794
Net investment income	250			220			708			628
Net realized gains on financial instruments	27			115			5			138
Other-than-temporary impairment losses recognized in income	(6		)	(6		)	(18		)	(21		)
Interest expense	(188		)	(150		)	(564		)	(575		)
Amortization of other intangible assets	(91		)	(42		)	(265		)	(124		)
Gain (loss) on extinguishment of debt	1			—			(17		)	—
Income before income tax expense	$	1,242		$	1,119		$	4,525		$	3,840