At December 31 Year ended December 31
  Gross Investment at Cost Net Investment Additions at Cost1 Depreciation Expense2
2008 2007 2006 2008 2007 2006 2008 2007 2006 2008 2007 2006
1

Net of dry hole expense related to prior years' expenditures of $55, $89 and $120 in 2008, 2007 and 2006, respectively.
2

Depreciation expense includes accretion expense of $430, $399 and $275 in 2008, 2007 and 2006, respectively.
3

Primarily mining operations, power generation businesses, real estate assets and management information systems.
Upstream                        
United States $54,156 $50,991 $46,191 $22,294 $19,850 $16,706 $5,374 $5,725 $3,739 $2,683 $2,700 $2,374
International 84,282 71,408 61,281 51,140 43,431 37,730 13,177 10,512 7,290 5,441 4,605 3,888
Total Upstream 138,438 122,399 107,472 73,434 63,281 54,436 18,551 16,237 11,029 8,124 7,305 6,262
Downstream                        
United States 17,394 15,807 14,553 8,977 7,685 6,741 2,032 1,514 1,109 629 509 474
International 11,587 10,471 11,036 6,001 4,690 5,233 2,285 519 532 469 633 551
Total Downstream 28,981 26,278 25,589 14,978 12,375 11,974 4,317 2,033 1,641 1,098 1,142 1,025
Chemicals                        
United States 725 678 645 338 308 289 50 40 25 19 19 19
International 828 815 771 496 453 431 72 53 54 33 26 24
Total Chemicals 1,553 1,493 1,416 834 761 720 122 93 79 52 45 43
All Other3                        
United States 4,310 3,873 3,243 2,523 2,179 1,709 598 680 270 250 215 171
International 17 41 27 11 14 19 5 5 8 4 1 5
Total All Other 4,327 3,914 3,270 2,534 2,193 1,728 603 685 278 254 216 176
Total United States 76,585 71,349 64,632 34,132 30,022 25,445 8,054 7,959 5,143 3,581 3,443 3,038
Total International 96,714 82,735 73,115 57,648 48,588 43,413 15,539 11,089 7,884 5,947 5,265 4,468
Total $173,299 $154,084 $137,747 $91,780 $78,610 $68,858 $23,593 $19,048 $13,027 $9,528 $8,708 $7,506