At December 31 Year ended December 31
 
  Gross Investment at Cost Net Investment Additions at Cost1 Depreciation Expense2
2007 2006 2005 2007 2006 2005 2007 2006 2005 2007 2006 2005
1 Net of dry hole expense related to prior years' expenditures of $89, $120 and $28 in 2007, 2006 and 2005, respectively.
2 Depreciation expense includes accretion expense of $399, $275 and $187 in 2007, 2006 and 2005, respectively.
3 Primarily mining operations, power generation businesses, real estate assets and management information systems.
Upstream              
United States $50,991 $46,191 $43,390 $19,850 $16,706 $15,327 $5,725 $3,739 $2,160 $2,700 $2,374 $1,869
International 71,408 61,281 54,497 43,431 37,730 34,311 10,512 7,290 4,897 4,605 3,888 2,804
Total Upstream 122,399 107,472 97,887 63,281 54,436 49,638 16,237 11,029 7,057 7,305 6,262 4,673
Downstream              
United States 15,807 14,553 13,832 7,685 6,741 6,169 1,514 1,109 793 509 474 461
International 10,471 11,036 11,235 4,690 5,233 5,529 519 532 453 633 551 550
Total Downstream 26,278 25,589 25,067 12,375 11,974 11,698 2,033 1,641 1,246 1,142 1,025 1,011
Chemicals              
United States 678 645 624 308 289 282 40 25 12 19 19 19
International 815 771 721 453 431 402 53 54 43 26 24 23
Total Chemicals 1,493 1,416 1,345 761 720 684 93 79 55 45 43 42
All Other3              
United States 3,873 3,243 3,127 2,179 1,709 1,655 680 270 199 215 171 186
International 41 27 20 14 19 15 5 8 4 1 5 1
Total All Other 3,914 3,270 3,147 2,193 1,728 1,670 685 278 203 216 176 187
Total United States 71,349 64,632 60,973 30,022 25,445 23,433 7,959 5,143 3,164 3,443 3,038 2,535
Total International 82,735 73,115 66,473 48,588 43,413 40,257 11,089 7,884 5,397 5,265 4,468 3,378
Total $154,084 $137,747 $127,446 $78,610 $68,858 $63,690 $19,048 $13,027 $8,561 $8,708 $7,506 $5,913