Debt - Additional Information (Detail) (USD $)	1 Months Ended	3 Months Ended		9 Months Ended						9 Months Ended			1 Months Ended			9 Months Ended	1 Months Ended							1 Months Ended
	Oct. 31, 2012	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011	Dec. 31, 2011	May 31, 2012 Euro Dollar Rate Minimum	May 31, 2012 Base Rate	May 31, 2012 Base Rate Minimum	Sep. 30, 2012 Corporate revolving bank credit facility	May 31, 2012 Corporate revolving bank credit facility	Sep. 30, 2012 Corporate revolving bank credit facility Maximum	May 31, 2012 Oilfield Services Revolving Credit Facility Maximum	Sep. 30, 2012 Corporate revolving bank credit facility	Dec. 31, 2011 Corporate revolving bank credit facility	Sep. 30, 2012 Exchange Notes	Oct. 31, 2012 Term Loan	May 31, 2012 Term Loan	Sep. 30, 2012 Term Loan	Sep. 30, 2012 Term Loan Maximum	May 31, 2012 Term Loan Euro Dollar Rate	May 31, 2012 Term Loan Euro Dollar Rate If any amounts remain outstanding under the term loan credit agreement following January 1 2013	Sep. 30, 2012 Term Loan Euro Dollar Rate If prior to January 1 2013 net cash proceeds from certain asset dispositions and other asset sales transactions are used to repay amounts outstanding under corporate revolving bank credit facility	May 31, 2012 Term Loan Base Rate If any amounts remain outstanding under the term loan credit agreement following January 1 2013	Sep. 30, 2012 Term Loan Base Rate If prior to January 1 2013 net cash proceeds from certain asset dispositions and other asset sales transactions are used to repay amounts outstanding under corporate revolving bank credit facility
Debt Instrument [Line Items]
Debt Instrument, Unamortized Discount		$ 393,000,000		$ 393,000,000		$ 444,000,000												$ 120,000,000
Interest rate							1.50%		2.50%							11.50%
Unsecured Loan											4,000,000,000
Debt Instrument, Face Amount											4,000,000,000
Net proceeds from issuance of unsecured loan																		3,789,000,000
Discount on term loans																		3.00%
Debt Issuance Cost																		91,000,000
Line of credit facility, commitment fee percentage										0.50%			0.50%
Debt Instrument Interest Rate In Addition To Eurodollar Rate																		1.00%	1.00%
Debt Instrument, Basis Spread on Variable Rate								6.00%													7.00%	10.00%	8.00%	9.00%	7.00%
Proceeds from Sale of Property, Plant, and Equipment		4,000,000															4,000,000,000
Debt Instrument, Interest Rate During Period																								11.16%
Gains on sales of investments	155,000,000	31,000,000	0	1,061,000,000	0
Write off of Deferred Debt Issuance Cost																	86,000,000
Proceeds from (Repayments of) Short-term Debt	114,000,000
Increase (Decrease) in Interest Payable, Net	45,000,000
Long-term Debt, Gross		$ 16,218,000,000		$ 16,218,000,000		$ 10,626,000,000						$ 125,000,000		$ 1,785,000,000	$ 1,719,000,000					$ 125,000,000
Debt maturity date																Dec. 02, 2017