CONSOLIDATED STATEMENT OF COMPREHENSIVE INCOME (LOSS) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Statement Of Income And Comprehensive Income [Abstract]
Net income (loss)	$ (10,486)	$ (10,107)	$ 2,177
Currency translation adjustments
Net change arising during the period	(239)	67	(191)
Marketable securities
Unrealized loss arising during the period			(11)
Cash flow hedges
Net loss on cash flow hedges	(90)	(32)	(16)
Reclassification to net income (loss) of net realized loss	54	10	1
Pension and other postretirement benefit plans
Actuarial gain (loss) arising during the period	(247)	127	(186)
Amortization to net income (loss) of net actuarial loss	200	94	187
Amortization to net income (loss) of net prior service (credit) cost	(17)	(11)	(5)
Impact of curtailment	(69)
Income taxes on pension and other postretirement benefit plans	(38)	(71)	(18)
Comprehensive income (loss)	(10,932)	(9,923)	1,938
Comprehensive income attributable to noncontrolling interests	32	30	39
Comprehensive income (loss) attributable to Schlumberger	$ (10,964)	$ (9,953)	$ 1,899