Consolidated Statement of Comprehensive Income (Parenthetical) - USD ($) $ in Millions	12 Months Ended
Dec. 31, 2023	Dec. 31, 2022
Statement Of Comprehensive Income [Line Items]
Gains / (losses) on defined benefit plans, before tax	$ 110	$ (73)
Major Defined Benefit Plans [Member]
Statement Of Comprehensive Income [Line Items]
Gains / (losses) on defined benefit plans, before tax	111	(80)
Swiss Defined Benefit Plans [Member]
Statement Of Comprehensive Income [Line Items]
Gains / (losses) on defined benefit plans, before tax	124	(285)
UK Defined Benefit Plans [Member]
Statement Of Comprehensive Income [Line Items]
Gains / (losses) on defined benefit plans, before tax	$ (41)	$ 162

The amount of other comprehensive income, before tax, related to gains (losses) on remeasurements of defined benefit plans, which comprise actuarial gains and losses; the return on plan assets, excluding amounts included in net interest on the net defined benefit liability (asset); and any change in the effect of the asset ceiling, excluding amounts included in net interest on the net defined benefit liability (asset). [Refer: Other comprehensive income; Defined benefit plans [member]; Plan assets [member]; Net defined benefit liability (asset)] [Contrast: Decrease (increase) in net defined benefit liability (asset) resulting from gain (loss) on remeasurement in other comprehensive income]

Reference 1: http://www.xbrl.org/2009/role/commonPracticeRef
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Reference 2: http://www.xbrl.org/2003/role/disclosureRef
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Reference 3: http://www.xbrl.org/2003/role/disclosureRef
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