CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2018	Sep. 30, 2017	Sep. 30, 2018	Sep. 30, 2017
Statement Of Income And Comprehensive Income [Abstract]
Net income	$ 658	$ 556	$ 1,628	$ 758
Currency translation adjustments
Unrealized net change arising during the period	(47)	75	(128)	49
Marketable securities
Unrealized loss arising during the period	(12)	(41)	(33)	(66)
Cash flow hedges
Net gain (loss) on cash flow hedges	4	8	(6)	19
Reclassification to net income of net realized (gain) loss	2	(4)	(2)	4
Pension and other postretirement benefit plans
Amortization to net income of net actuarial loss	47	40	141	119
Amortization to net income of net prior service (credit) cost	(1)	20	(4)	60
Income taxes on pension and other postretirement benefit plans	(2)		(7)	(2)
Comprehensive income	649	654	1,589	941
Comprehensive income attributable to noncontrolling interests	14	11	29	9
Comprehensive income attributable to Schlumberger	$ 635	$ 643	$ 1,560	$ 932