Inventories (Details) (USD $) In Millions	Sep. 30, 2011	Dec. 31, 2010
Inventories
Raw materials	$ 68	$ 63
Materials and supplies	459	414
Finished goods	794	636
Inventories, Gross	1,321	1,113
LIFO reserve	(72)	(72)
Total	$ 1,249	$ 1,041

Name:	oxy_InventoriesDisclosureAbstract
Namespace Prefix:	oxy
Data Type:	xbrli:stringItemType
Balance Type:	na
Period Type:	duration

Carrying amount as of the balance sheet date of merchandise or goods held by the company that are readily available for sale.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 6

-Subparagraph a

-Article 5

+ Details

Name:	us-gaap_InventoryFinishedGoods
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Carrying amount as of the balance sheet date of merchandise, goods, commodities, or supplies held for future sale or to be used in manufacturing, servicing or production process.

+ Details

Name:	us-gaap_InventoryGross
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Reflects the difference between (a) inventory at the lower of LIFO cost or market and (b) inventory at replacement cost or at the lower of some acceptable inventory accounting method (such as FIFO or average cost), or market. If material, reflects an excess of replacement or current cost over stated LIFO value parenthetically on the balance sheet or in a note to the financial statements.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 6

-Subparagraph c

-Article 5

+ Details

Name:	us-gaap_InventoryLIFOReserve
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant

- Definition

Carrying amount (lower of cost or market) as of the balance sheet date of inventories less all valuation and other allowances. Excludes noncurrent inventory balances (expected to remain on hand past one year or one operating cycle, if longer).

+ Details

Name:	us-gaap_InventoryNet
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Carrying amount as of the balance sheet date of unprocessed items to be consumed in the manufacturing or production process. Also includes purchased parts that will be used as components of a finished product.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 6

-Subparagraph a

-Article 5

+ Details

Name:	us-gaap_InventoryRawMaterials
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant

- Definition

Carrying amount as of the balance sheet date of products used directly or indirectly in the manufacturing or production process, which may or may not become part of the final product. May also include items used in the storage, presentation or transportation of physical goods.

+ References

Reference 1: http://www.xbrl.org/2003/role/presentationRef

-Publisher SEC

-Name Regulation S-X (SX)

-Number 210

-Section 02

-Paragraph 6

-Subparagraph a

-Article 5

Reference 2: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 43

-Chapter 3

-Section A

-Paragraph 9

Reference 3: http://www.xbrl.org/2003/role/presentationRef

-Publisher AICPA

-Name Accounting Research Bulletin (ARB)

-Number 43

-Chapter 4

-Paragraph 3

+ Details

Name:	us-gaap_OtherInventorySupplies
Namespace Prefix:	us-gaap
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	instant