Pension and Other Postretirement Benefits - Net Pension Cost for Schlumberger Pension Plans and US Postretirement Medical Plan (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
US Plan Assets
Defined Benefit Plan Disclosure [Line Items]
Service cost — benefits earned during period	$ 19	$ 17	$ 60	$ 51
Interest cost on benefit obligation	38	38	113	114
Expected return on plan assets	(47)	(46)	(150)	(139)
Amortization of prior service cost	3	3	9	9
Amortization of net loss	28	26	91	72
Total pension cost	41	38	123	107
International
Defined Benefit Plan Disclosure [Line Items]
Service cost — benefits earned during period	28	21	95	63
Interest cost on benefit obligation	65	62	189	178
Expected return on plan assets	(88)	(82)	(288)	(242)
Amortization of prior service cost	29	30	88	90
Amortization of net loss	42	22	116	52
Total pension cost	76	53	200	141
Postretirement medical plan
Defined Benefit Plan Disclosure [Line Items]
Service cost — benefits earned during period	12	7	36	21
Interest cost on benefit obligation	14	14	42	44
Expected return on plan assets	(9)	(8)	(28)	(22)
Amortization of prior service cost	(1)	(2)	(3)	(6)
Amortization of net loss	2	3	17	13
Total pension cost	$ 18	$ 14	$ 64	$ 50