Income Taxes - Additional Information (Detail) (USD $)	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Income Tax [Line Items]
Write-down of oil and gas properties	$ 1,900,000,000
Undistributed earnings of the foreign subsidiaries	15,900,000,000
Tax expenses recorded	5,000,000	6,000,000	12,000,000
Accrued for payment of interest and penalties	6,000,000	42,000,000
Settlements	65,000,000	22,000,000
United States [Member]
Income Tax [Line Items]
Operating loss carryforwards	2,393,000,000
Mariner Energy Inc [Member]
Income Tax [Line Items]
Operating loss carryforwards	543,000,000
Cordillera Energy Partners [Member]
Income Tax [Line Items]
Operating loss carryforwards	183,000,000
Canada [Member]
Income Tax [Line Items]
Operating loss carryforwards	6,000,000
Capital loss carryforwards	$ 170,000,000