SEGMENT INFORMATION

We have five operating segments: Aerospace, Combat Systems, Information Technology, Mission Systems, and Marine Systems. We organize our segments in accordance with the nature of products and services offered. We measure each segment’s profitability based on operating earnings. As a result, we do not allocate net interest, other income and expense items, and income taxes to our segments.

Summary financial information for each of our segments follows:



	Revenue						Operating Earnings								Revenue from U.S. Government
Year Ended December 31	2018		2017		2016		2018			2017		2016			2018		2017		2016
Aerospace	$	8,455	$	8,129	$	7,815	$	1,490		$	1,577	$	1,394		$	334	$	231	$	361
Combat Systems	6,241		5,949		5,530		962			937		831			3,228		3,084		2,614
Information Technology	8,269		4,410		4,428		608			373		340			8,025		4,164		4,147
Mission Systems	4,726		4,481		4,716		659			638		601			3,774		3,629		3,837
Marine Systems	8,502		8,004		8,072		761			685		595			8,245		7,913		7,717
Corporate	—		—		—		(23		)	26		(17		)	—		—		—
Total	$	36,193	$	30,973	$	30,561	$	4,457		$	4,236	$	3,744		$	23,606	$	19,021	$	18,676

Corporate operating results have two primary components: pension and other post-retirement benefit income, and stock option expense. ASU 2017-07 requires the non-service cost components of pension and other post-retirement benefit cost (e.g., interest cost) to be reported in other income (expense) in the Consolidated Statement of Earnings. In our defense segments, as described in Note Q, pension and other post-retirement benefit costs are allocable contract costs. For these segments, we report the offset for the non-service cost components in Corporate operating results. Corporate operating results in 2018 also included one-time charges of approximately $45 associated with the costs to complete the CSRA acquisition.

The following is additional summary financial information for each of our segments:



	Identifiable Assets						Capital Expenditures						Depreciation and Amortization
Year Ended December 31	2018		2017		2016		2018		2017		2016		2018		2017		2016
Aerospace	$	11,220	$	10,126	$	9,792	$	194	$	132	$	125	$	154	$	147	$	153
Combat Systems	9,853		9,846		8,885		91		84		71		87		86		86
Information Technology	14,159		3,021		2,778		62		16		10		333		32		42
Mission Systems	5,984		5,856		5,667		49		47		87		65		60		61
Marine Systems	3,130		2,906		3,063		243		123		92		116		109		105
Corporate*	1,062		3,291		2,987		51		26		7		8		7		6
Total	$	45,408	$	35,046	$	33,172	$	690	$	428	$	392	$	763	$	441	$	453

* Corporate identifiable assets are primarily cash and equivalents.

See Note C for additional revenue information by segment.

The following table presents our revenue by geographic area based on the location of our customers:



Year Ended December 31	2018		2017		2016
North America:
United States	$	28,578	$	23,519	$	23,160
Other	755		915		709
Total North America	29,333		24,434		23,869
Europe	2,772		2,558		2,152
Asia/Pacific	2,252		2,011		1,650
Africa/Middle East	1,565		1,655		2,617
South America	271		315		273
Total revenue	$	36,193	$	30,973	$	30,561

Our revenue from non-U.S. operations was $4.2 billion in 2018 and $3.7 billion in 2017 and 2016, and earnings from continuing operations before income taxes from non-U.S. operations were $578 in 2018, $550 in 2017 and $530 in 2016. The long-lived assets associated with these operations were 3% of our total long-lived assets on December 31, 2018, and 5% for December 31, 2017 and 2016.