Debt - Long-Term Debt Table (Details) (USD $) In Millions, except Per Share data, unless otherwise specified	3 Months Ended									3 Months Ended																																									0 Months Ended		0 Months Ended
	Mar. 31, 2014	Dec. 31, 2013	Mar. 31, 2014 Corporate Revolving Bank Credit Facility	Dec. 31, 2013 Corporate Revolving Bank Credit Facility	Mar. 31, 2014 Oilfield Services Revolving Bank Credit Facility	Dec. 31, 2013 Oilfield Services Revolving Bank Credit Facility	Mar. 31, 2014 Interest rate contract	Dec. 31, 2013 Interest rate contract	Mar. 31, 2014 6.875% Senior Notes Due 2018	Mar. 31, 2014 2.75% Contingent Convertible Senior Notes Due 2035	Mar. 31, 2014 2.5% Contingent Convertible Senior Notes due 2037	Mar. 31, 2014 2.25% Contingent Convertible Senior Notes Due 2038	Mar. 31, 2014 Term Loan [Member] Senior Secured Term Loan Due 2017	Dec. 31, 2013 Term Loan [Member] Senior Secured Term Loan Due 2017	Mar. 31, 2014 Senior Notes	Dec. 31, 2013 Senior Notes	Mar. 31, 2014 Senior Notes 9.5% Senior Notes Due 2015	Dec. 31, 2013 Senior Notes 9.5% Senior Notes Due 2015	Mar. 31, 2014 Senior Notes 3.25% Senior Notes due 2016	Dec. 31, 2013 Senior Notes 3.25% Senior Notes due 2016	Mar. 31, 2014 Senior Notes 6.25% Euro-Denominated Senior Notes Due 2017	Dec. 31, 2013 Senior Notes 6.25% Euro-Denominated Senior Notes Due 2017	Mar. 31, 2014 Senior Notes 6.25% Euro-Denominated Senior Notes Due 2017 Cross Currency Interest Rate Contract [Member]	Dec. 31, 2013 Senior Notes 6.25% Euro-Denominated Senior Notes Due 2017 Cross Currency Interest Rate Contract [Member]	Mar. 31, 2014 Senior Notes 6.5% Senior Notes Due 2017	Dec. 31, 2013 Senior Notes 6.5% Senior Notes Due 2017	Mar. 31, 2014 Senior Notes 6.875% Senior Notes Due 2018	Dec. 31, 2013 Senior Notes 6.875% Senior Notes Due 2018	Mar. 31, 2014 Senior Notes 7.25% Senior Notes Due 2018	Dec. 31, 2013 Senior Notes 7.25% Senior Notes Due 2018	Mar. 31, 2014 Senior Notes 6.625% Senior Notes Due 2019	Dec. 31, 2013 Senior Notes 6.625% Senior Notes Due 2019	Mar. 31, 2014 Senior Notes 6.625% Senior Notes Due 2020	Dec. 31, 2013 Senior Notes 6.625% Senior Notes Due 2020	Mar. 31, 2014 Senior Notes 6.875% Senior Notes Due 2020	Dec. 31, 2013 Senior Notes 6.875% Senior Notes Due 2020	Mar. 31, 2014 Senior Notes 6.125% Senior Notes Due 2021	Dec. 31, 2013 Senior Notes 6.125% Senior Notes Due 2021	Mar. 31, 2014 Senior Notes 5.375% Senior Notes due 2021	Dec. 31, 2013 Senior Notes 5.375% Senior Notes due 2021	Mar. 31, 2014 Senior Notes 5.75% Senior Notes due 2023	Dec. 31, 2013 Senior Notes 5.75% Senior Notes due 2023	Mar. 31, 2014 Senior Notes 2.75% Contingent Convertible Senior Notes Due 2035	Dec. 31, 2013 Senior Notes 2.75% Contingent Convertible Senior Notes Due 2035	Mar. 31, 2014 Senior Notes 2.5% Contingent Convertible Senior Notes due 2037	Dec. 31, 2013 Senior Notes 2.5% Contingent Convertible Senior Notes due 2037	Mar. 31, 2014 Senior Notes 2.25% Contingent Convertible Senior Notes Due 2038	Dec. 31, 2013 Senior Notes 2.25% Contingent Convertible Senior Notes Due 2038	Mar. 31, 2014 Note Discounts [Member]	Dec. 31, 2013 Note Discounts [Member]	Apr. 25, 2014 Subsequent Event [Member] Senior Notes	Apr. 24, 2014 Subsequent Event [Member] Senior Notes	Apr. 25, 2014 Subsequent Event [Member] Senior Notes 9.5% Senior Notes Due 2015	Apr. 24, 2014 Subsequent Event [Member] Senior Notes 9.5% Senior Notes Due 2015	Apr. 10, 2014 Subsequent Event [Member] Senior Notes 9.5% Senior Notes Due 2015	Mar. 31, 2014 Subsequent Event [Member] Senior Notes 6.875% Senior Notes Due 2018
Long-Term Debt Instrument [Line Items]
Long-term Debt, Gross	$ 12,969	$ 12,886	$ 0	$ 0	$ 464	$ 405	$ 13	$ 13					$ 2,000	$ 2,000			$ 1,265	$ 1,265	$ 500	$ 500	$ 473	$ 473	$ 473		$ 660	$ 660	$ 97	$ 97	$ 669	$ 669	$ 650	$ 650	$ 1,300	$ 1,300	$ 500	$ 500	$ 1,000	$ 1,000	$ 700	$ 700	$ 1,100	$ 1,100	$ 396	$ 396	$ 1,168	$ 1,168	$ 347	$ 347				$ 3,000		$ 319
Current maturities of long-term debt, net	(316)	0
Repayments of Notes Payable																																																			946		946
Long-term Debt, Excluding Current Maturities	12,653	12,886
Debt Instrument, Unamortized Discount													$ 30	$ 33	$ 284	$ 303																																	$ (333)	$ (357)				$ 3
Derivative, Forward Exchange Rate																							1.3769	1.3743
Debt Instrument, Interest Rate, Stated Percentage									6.625%								9.50%		3.25%				6.25%		6.50%		6.875%		7.25%		6.625%		6.625%		6.875%		6.125%		5.375%		5.75%		2.75%		2.50%		2.25%								9.50%	6.875%
Percentage Of Principal Amount Of Notes For Repurchase Requirement Of Contingent Convertible Senior Notes	100.00%
Debt Instrument, Convertible, Terms of Conversion Feature	5
Common Stock Price Conversion Thresholds										$ 48.09	$ 63.62	$ 106.75
Debt Instrument, Date of First Required Payment										May 14, 2016	Nov. 14, 2017	Jun. 14, 2019