Business Segment and Geographic Information (Details) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Business Segment and Geographic Information [Abstract]
Number of business segments	2
Revenue:
Total revenue	$ 24,829	$ 17,973	$ 14,675
Operating income:
Total operating income	4,737	3,009	1,994
Interest expense, net of interest income	(263)	(297)	(285)
Other, net	(25)	(57)	(27)
Income from continuing operations before income taxes	4,449	2,655	1,682
Capital expenditures:
Total capital expenditures	2,953	2,069	1,864
Depreciation, depletion, and amortization:
Total depreciation, depletion and amortization	1,359	1,119	931
Total assets:
Total assets	23,677	18,297
Operations by geographic area, Revenue:
United States	13,548	8,209	5,248
Other countries	11,281	9,764	9,427
Total revenue	24,829	17,973	14,675
Operations by geographic area, Long-lived assets:
United States	6,692	5,389
Other countries	5,189	3,821
Long-lived assets	11,881	9,210
Completion and Production [Member]
Revenue:
Total revenue	15,143	9,997	7,419
Operating income:
Total operating income	3,733	2,032	1,016
Capital expenditures:
Total capital expenditures	1,669	1,010	900
Depreciation, depletion, and amortization:
Total depreciation, depletion and amortization	680	537	437
Total assets:
Total assets	10,953	7,815
Operations by geographic area, Revenue:
Total revenue	15,143	9,997	7,419
Drilling and Evaluation [Member]
Revenue:
Total revenue	9,686	7,976	7,256
Operating income:
Total operating income	1,403	1,213	1,183
Capital expenditures:
Total capital expenditures	1,231	1,058	959
Depreciation, depletion, and amortization:
Total depreciation, depletion and amortization	676	578	490
Total assets:
Total assets	8,212	7,088
Operations by geographic area, Revenue:
Total revenue	9,686	7,976	7,256
Total Operating Segments [Member]
Operating income:
Total operating income	5,136	3,245	2,199
Shared assets [Member]
Total assets:
Total assets	1,249	942
Corporate and other [Member]
Operating income:
Total operating income	(399)	(236)	(205)
Capital expenditures:
Total capital expenditures	53	1	5
Depreciation, depletion, and amortization:
Total depreciation, depletion and amortization	3	4	4
Total assets:
Total assets	$ 3,263	$ 2,452