Benefit Plans - Components of Net Periodic Pension Cost (Details) - Pension Plans - USD ($) $ in Millions		9 Months Ended	12 Months Ended
		Sep. 30, 2021	Dec. 31, 2021	Dec. 31, 2020	Dec. 31, 2019
Defined Benefit Plan Disclosure [Line Items]
Curtailment credit		$ 17
U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost			$ 6	$ 6	$ 38
Interest cost			42	49	60
Expected return on plan assets			(72)	(77)	(88)
Net loss/(gain)			17	17	30
Prior service cost/(benefit)			1	1	1
Curtailment credit	[1]		0	0	0
Settlement losses and other expenses			19	18	16
Net periodic postemployment costs			13	14	57
Non-U.S. Plans
Defined Benefit Plan Disclosure [Line Items]
Service cost			137	121	122
Interest cost			130	149	202
Expected return on plan assets			(419)	(400)	(404)
Net loss/(gain)			130	118	148
Prior service cost/(benefit)			(6)	(7)	(6)
Curtailment credit	[1]		(17)	0	0
Settlement losses and other expenses			3	4	(3)
Net periodic postemployment costs			(42)	$ (15)	$ 59
U.K.
Defined Benefit Plan Disclosure [Line Items]
Incentive payment charges and other expenses related to frozen benefit plan			$ 48

[1] During the third quarter of 2021, we terminated our Defined Benefit Pension Scheme in Nigeria. During the second quarter of 2021, we made a decision to freeze our Defined Benefit Pension Scheme in the United Kingdom. As a result, we recognized curtailment credits of ($17 million) in 2021 recorded within benefit plan non-service income. In connection with the United Kingdom plan freeze, we also incurred incentive payment charges and other expenses of $48 million in 2021 included in operating income.