CONSOLIDATED STATEMENT OF EQUITY (Parenthetical) (USD $) In Millions, unless otherwise specified	12 Months Ended
Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Paid-in Capital [Member]
Sale of subsidiary units, tax	$ 18
Conversion of subordinated limited partner units to common units, tax	82
Noncontrolling Interests [Member]
Sale of subsidiary units, tax	9	43	5
Conversion of subordinated limited partner units to common units, tax	$ (82)

Amount of tax associated with cumulative subsidiary equity transactions transferred from noncontrolling interests to paid-in capital upon conversion of subordinated limited partner units to common units.

No definition available.

Name:	apc_AmountOfNoncontrollingInterestsTransferredToPaidInCapitalUponConversionOfSubordinatedLimitedPartnerUnitsToCommonUnitsTax
Namespace Prefix:	apc_
Data Type:	xbrli:monetaryItemType
Balance Type:	debit
Period Type:	duration