RETIREMENT AND DEFERRED COMPENSATION PLANS (Tables)

12 Months Ended

Dec. 31, 2012

Changes in Benefit Obligation, Fair Value of Plan Assets and Funded Status of Pension and Postretirement Benefit Plans

The following tables set forth the benefit obligation, fair value of plan assets and funded status as of December 31, 2012, 2011, and 2010, and the underlying weighted average actuarial assumptions used for the U.K. Pension Plan and U.S. postretirement benefit plan. Apache uses a measurement date of December 31 for its pension and postretirement benefit plans.

	2012						2011						2010
	Pension Benefits			Postretirement Benefits			Pension Benefits			Postretirement Benefits			Pension Benefits			Postretirement Benefits
	(In millions)
Change in Projected Benefit Obligation
Projected benefit obligation beginning of year	$	150		$	30		$	136		$	29		$	135		$	18
Service cost		5			4			5			3			5			2
Interest cost		7			1			7			1			7			1
Foreign currency exchange rate changes		7			—			(1	)		—			(4	)		—
Amendments		—			—			—			—			—			—
Actuarial losses (gains)		14			1			6			(2	)		(1	)		8
Effect of curtailment and settlements		—			—			—			—			—			—
Benefits paid		(6	)		(1	)		(3	)		(1	)		(6	)		—
Retiree contributions		—			—			—			—			—			—
Projected benefit obligation at end of year		177			35			150			30			136			29
Change in Plan Assets
Fair value of plan assets at beginning of year		145			—			135			—			118			—
Actual return on plan assets		14			—			4			—			14			—
Foreign currency exchange rates		6			—			(1	)		—			(3	)		—
Employer contributions		11			1			10			1			12			—
Benefits paid		(6	)		(1	)		(3	)		(1	)		(6	)		—
Retiree contributions		—			—			—			—			—			—
Fair value of plan assets at end of year		170			—			145			—			135			—
Funded status at end of year	$	(7	)	$	(35	)	$	(5	)	$	(30	)	$	(1	)	$	(29	)
Amounts recognized in Consolidated Balance Sheet
Current liability		—			(1	)		—			(1	)		—			(1	)
Non-current liability		(7	)		(34	)		(5	)		(29	)		(1	)		(28	)
	$	(7	)	$	(35	)	$	(5	)	$	(30	)	$	(1	)	$	(29	)
Pre-tax Amounts Recognized in Accumulated Other Comprehensive Income (Loss)
Accumulated (loss)		(32	)		(7	)		(25	)		(6	)		(15	)		(8	)
Prior service cost		—			—			—			—			—			—
Transition asset (obligation)		—			—			—			—			—			—
	$	(32	)	$	(7	)	$	(25	)	$	(6	)	$	(15	)	$	(8	)
Weighted Average Assumptions used as of December 31
Discount rate		4.30	%		3.43	%		4.70	%		4.04	%		5.40	%		4.93	%
Salary increases		4.60	%		N/A			4.60	%		N/A			5.00	%		N/A
Expected return on assets		4.70	%		N/A			4.85	%		N/A			6.25	%		N/A
Healthcare cost trend
Initial		N/A			7.25	%		N/A			7.50	%		N/A			8.00	%
Ultimate in 2022		N/A			5.00	%		N/A			5.00	%		N/A			5.00	%

Allocations for Plan Asset Holding and Target Allocation for Company's Plan Asset

A breakout of previous allocations for plan asset holdings and the target allocation for the Company’s plan assets are summarized below:

	Target Allocation			Percentage of Plan Assets at Year-End
	2012			2012			2011
Asset Category
Equity securities:
U.K. quoted equities		17	%		16	%		17	%
Overseas quoted equities		33	%		33	%		31	%
Total equity securities		50	%		49	%		48	%
Debt securities:
U.K. Government bonds		30	%		30	%		30	%
U.K. corporate bonds		20	%		20	%		18	%
Debt securities		50	%		50	%		48	%
Cash		0	%		1	%		4	%
Total		100	%		100	%		100	%

Fair Values of Plan Assets for Each Major Asset Category Based on Nature and Significant Concentration of Risks in Plan Assets

The following table presents the fair values of plan assets for each major asset category based on the nature and significant concentration of risks in plan assets at December 31, 2012:

	Fair Value Measurements Using:
	Quoted Price in Active Markets (Level 1)		Significant Other Inputs (Level 2)		Unobservable Inputs (Level 3)		Total Fair Value
	(In millions)
Equity securities:
U.K. quoted equities(1)	$	28	$	—	$	—	$	28
Overseas quoted equities(2)		56		—		—		56
Total equity securities		84		—		—		84
Debt securities:
U.K. Government bonds(3)		51		—		—		51
U.K. corporate bonds(4)		34		—		—		34
Total debt securities		85		—		—		85
Cash		1		—		—		1
Fair value of plan assets	$	170	$	—	$	—	$	170

(1) This category comprises U.K. equities, which are benchmarked against the FTSE All-Share Index.

(2) This category includes overseas equities, which comprises 85 percent global equities benchmarked against the MSCI World Index and 15 percent emerging markets benchmarked against the MSCI Emerging Markets Index, both of which have a performance target of 2 percent per annum over the benchmark over a rolling three-year period.

(3) This category includes U.K. Government bonds: 33 percent benchmarked against iBoxx Sterling Overall Gilt Index, with a performance target of 0.75 percent per annum over the benchmark over a rolling three-year period; and 67 percent against the FTSE Actuaries Government Securities Index-Linked Over 5 Years Index.

(4) This category comprises U.K. corporate bonds: 50 percent benchmarked against iBoxx Sterling Overall Non Gilt index with a performance target of 0.75 percent per annum over the benchmark over a rolling three-year period; and 50 percent benchmarked against the iBoxx Sterling Overall Non Gilt Index with a performance target of 0.75 percent per annum over the benchmark over a rolling five year period.

The following table presents the fair values of plan assets for each major asset category based on the nature and significant concentration of risks in plan assets at December 31, 2011:

	Fair Value Measurements Using:
	Quoted Price in Active Markets (Level 1)		Significant Other Inputs (Level 2)		Unobservable Inputs (Level 3)		Total Fair Value
	(In millions)
Equity securities:
U.K. quoted equities(1)	$	24	$	—	$	—	$	24
Overseas quoted equities(2)		46		—		—		46
Total equity securities		70		—		—		70
Debt securities:
U.K. Government bonds(3)		43		—		—		43
U.K. corporate bonds(4)		26		—		—		26
Total debt securities		69		—		—		69
Cash		6		—		—		6
Fair value of plan assets	$	145	$	—	$	—	$	145

(1) This category comprises U.K. equities, which are benchmarked against the FTSE All-Share Index.

(2) This category includes overseas equities, which comprises 85 percent global equities benchmarked against the MSCI World Index and 15 percent emerging markets benchmarked against the MSCI Emerging Markets Index, both of which have a performance target of 2 percent per annum over the benchmark over a rolling three-year period.

(3) This category includes U.K. Government bonds: 72 percent benchmarked against iBoxx Sterling Overall Index, with a performance target of 0.75 percent per annum over the benchmark over a rolling three-year period; and 28 percent against the FTSE Actuaries Government Securities Index-Linked Over 5 Years Index.

(4) This category comprises U.K. corporate bonds benchmarked against the iBoxx Sterling Overall Index.

Components of Net Periodic Cost and Underlying Weighted Average Actuarial Assumptions Used for Pension and Postretirement Benefit Plans

The following tables set forth the components of the net periodic cost and the underlying weighted average actuarial assumptions used for the pension and postretirement benefit plans as of December 31, 2012, 2011, and 2010:

	2012						2011						2010
	Pension Benefits			Postretirement Benefits			Pension Benefits			Postretirement Benefits			Pension Benefits			Postretirement Benefits
	(In millions)
Component of Net Periodic Benefit Costs
Service cost	$	5		$	4		$	5		$	3		$	5		$	2
Interest cost		7			1			7			1			7			1
Expected return on assets		(7	)		—			(8	)		—			(8	)		—
Amortization of actuarial gain (loss)		1			—			—			—			1			—
Net periodic benefit cost	$	6		$	5		$	4		$	4		$	5		$	3
Weighted Average Assumptions used to determine Net Period Benefit Cost for the Years ended December 31
Discount rate		4.70	%		4.04	%		5.40	%		4.93	%		5.70	%		5.56	%
Salary increases		4.60	%		N/A			5.00	%		N/A			5.30	%		N/A
Expected return on assets		4.85	%		N/A			6.25	%		N/A			6.65	%		N/A
Healthcare cost trend
Initial		—			7.50	%		—			8.00	%		—			7.50	%
Ultimate in 2017		—			5.00	%		—			5.00	%		—			5.00	%

Effect of One-Percentage-Point Change in Assumed Health Care Cost Trend Rates

A one-percentage-point change in assumed health care cost trend rates would have the following effects:

	Postretirement Benefits
	1% Increase		1% Decrease
	(In millions)
Effect on service and interest cost components	$	1	$	(1	)
Effect on postretirement benefit obligation		8		(6	)

Expected Future Benefit Payment

The following benefit payments, which reflect expected future service, as appropriate, are expected to be paid:

	Pension Benefits		Postretirement Benefits
	(In millions)
2013	$	5	$	1
2014		6		1
2015		7		2
2016		7		2
2017		6		3
Years 2018 – 2022		49		18