Although each subsidiary of Chevron is responsible for its own affairs, Chevron Corporation manages its investments in these subsidiaries and their affiliates. For this purpose, the investments are grouped as follows: upstream — exploration and production; downstream — refining, marketing and transportation; chemicals; and all other. The first three of these groupings represent the company's "reportable segments" and "operating segments" as defined in Financial Accounting Standards Board (FASB) Statement No. 131, Disclosures About Segments of an Enterprise and Related Information (FAS 131).

The segments are separately managed for investment purposes under a structure that includes "segment managers" who report to the company's "chief operating decision maker" (CODM) (terms as defined in FAS 131). The CODM is the company's Executive Committee, a committee of senior officers that includes the Chief Executive Officer and that, in turn, reports to the Board of Directors of Chevron Corporation.

The operating segments represent components of the company as described in FAS 131 terms that engage in activities (a) from which revenues are earned and expenses are incurred; (b) whose operating results are regularly reviewed by the CODM, which makes decisions about resources to be allocated to the segments and to assess their performance; and (c) for which discrete financial information is available.

Segment managers for the reportable segments are accountable directly to and maintain regular contact with the company's CODM to discuss the segment's operating activities and financial performance. The CODM approves annual capital and exploratory budgets at the reportable segment level, as well as reviews capital and exploratory funding for major projects and approves major changes to the annual capital and exploratory budgets. However, business-unit managers within the operating segments are directly responsible for decisions relating to project implementation and all other matters connected with daily operations. Company officers who are members of the Executive Committee also have individual management responsibilities and participate in other committees for purposes other than acting as the CODM.

"All Other" activities include the company's interest in Dynegy (through May 2007, when Chevron sold its interest), mining operations, power generation businesses, worldwide cash management and debt financing activities, corporate administrative functions, insurance operations, real estate activities, alternative fuels, and technology companies.

The company's primary country of operation is the United States of America, its country of domicile. Other components of the company's operations are reported as "International" (outside the United States).

Segment Earnings

The company evaluates the performance of its operating segments on an after-tax basis, without considering the effects of debt financing interest expense or investment interest income, both of which are managed by the company on a worldwide basis. Corporate administrative costs and assets are not allocated to the operating segments. However, operating segments are billed for the direct use of corporate services. Nonbillable costs remain at the corporate level in "All Other." After-tax segment income by major operating area is presented in the following table:

Year ended December 31
2007 2006 2005
Income by Major Operating Area
Upstream
United States $4,532 $4,270 $4,168
International 10,284 8,872 7,556
Total Upstream 14,816 13,142 11,724
Downstream
United States 966 1,938 980
International 2,536 2,035 1,786
Total Downstream 3,502 3,973 2,766
Chemicals
United States 253 430 240
International 143 109 58
Total Chemicals 396 539 298
Total Segment Income 18,714 17,654 14,788
All Other
Interest expense (107) (312) (337)
Interest income 385 380 266
Other (304) (584) (618)
Net Income $18,688 $17,138 $14,099

Segment Assets

Segment assets do not include intercompany investments or intercompany receivables. Segment assets at year‑end 2007 and 2006 are as follows:

At December 31
2007 2006
* "All Other" assets consist primarily of worldwide cash, cash equivalents and marketable securities, real estate, information systems, the company's investment in Dynegy prior to its disposition in 2007, mining operations, power generation businesses, technology companies, and assets of the corporate administrative functions.
Upstream
United States $23,535 $20,727
International 61,049 51,844
Goodwill 4,637 4,623
Total Upstream 89,221 77,194
Downstream
United States 16,790 13,482
International 26,075 22,892
Total Downstream 42,865 36,374
Chemicals
United States 2,484 2,568
International 870 832
Total Chemicals 3,354 3,400
Total Segment Assets 135,440 116,968
All Other*
United States 6,847 8,481
International 6,499 7,179
Total All Other 13,346 15,660
Total Assets – United States 49,656 45,258
Total Assets – International 94,493 82,747
Goodwill 4,637 4,623
Total Assets $148,786 $132,628

Segment Sales and Other Operating Revenues

Operating segment sales and other operating revenues, including internal transfers, for the years 2007, 2006 and 2005 are presented in the following table. Products are transferred between operating segments at internal product values that approximate market prices.

Revenues for the upstream segment are derived primarily from the production and sale of crude oil and natural gas, as well as the sale of third-party production of natural gas. Revenues for the downstream segment are derived from the refining and marketing of petroleum products, such as gasoline, jet fuel, gas oils, kerosene, lubricants, residual fuel oils and other products derived from crude oil. This segment also generates revenues from the transportation and trading of crude oil and refined products. Revenues for the chemicals segment are derived primarily from the manufacture and sale of additives for lubricants and fuel. "All Other" activities include revenues from mining operations of coal and other minerals, power generation businesses, insurance operations, real estate activities, and technology companies.

Other than the United States, no single country accounted for 10 percent or more of the company's total sales and other operating revenues in 2007.

Year ended December 31
2007 2006 2005
* Includes buy/sell contracts of $6,725 in 2006 and $23,822 in 2005. Substantially all of the amounts in each period relate to the downstream segment. Refer to Note 13 for a discussion of the company's accounting for buy/sell contracts.
Upstream
United States $18,736 $18,061 $16,044
Intersegment 11,625 10,069 8,651
Total United States 30,361 28,130 24,695
International 15,213 14,560 10,190
Intersegment 19,647 17,139 13,652
Total International 34,860 31,699 23,842
Total Upstream 65,221 59,829 48,537
Downstream
United States 70,535 69,367 73,721
Excise and similar taxes 4,990 4,829 4,521
Intersegment 491 533 535
Total United States 76,016 74,729 78,777
International 97,178 91,325 83,223
Excise and similar taxes 5,042 4,657 4,184
Intersegment 38 37 14
Total International 102,258 96,019 87,421
Total Downstream 178,274 170,748 166,198
Chemicals
United States 351 372 343
Excise and similar taxes 2 2
Intersegment 235 243 241
Total United States 588 617 584
International 1,143 959 760
Excise and similar taxes 86 63 14
Intersegment 142 160 131
Total International 1,371 1,182 905
Total Chemicals 1,959 1,799 1,489
All Other
United States 757 653 597
Intersegment 760 584 514
Total United States 1,517 1,237 1,111
International 58 44 44
Intersegment 31 23 26
Total International 89 67 70
Total All Other 1,606 1,304 1,181
Segment Sales and Other Operating Revenues
United States 108,482 104,713 105,167
International 138,578 128,967 112,238
Total Segment Sales and Other Operating Revenues 247,060 233,680 217,405
Elimination of intersegment sales (32,969) (28,788) (23,764)
Total Sales and Other Operating Revenues* $214,091 $204,892 $193,641

Segment Income Taxes

Segment income tax expense for the years 2007, 2006 and 2005 are as follows:

Year ended December 31
2007 2006 2005
Upstream
United States $2,541 $2,668 $2,330
International 11,307 10,987 8,440
Total Upstream 13,848 13,655 10,770
Downstream
United States 520 1,162 575
International 400 586 576
Total Downstream 920 1,748 1,151
Chemicals
United States 6 213 99
International 36 30 25
Total Chemicals 42 243 124
All Other (1,331) (808) (947)
Total Income Tax Expense $13,479 $14,838 $11,098

Other Segment Information

Additional information for the segmentation of major equity affiliates is contained in Note 11. Information related to properties, plant and equipment by segment is contained in Note 12.