Pensions Benefit Plans and Other Postretirement Benefits - Changes in the Benefit Obligation (Details) - Funded Plan - USD ($) $ in Millions	3 Months Ended	12 Months Ended
	Sep. 30, 2020	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Pension Benefit Plans | U.S.
Changes in the pension and postretirement benefit obligations
Obligations at beginning of year		$ 1,505	$ 1,413
Change in benefit obligations:
Service cost		11	12	$ 14
Interest cost		50	58	59
Actuarial (gain) loss		134	144
Settlements		(24)	(35)
Benefit payments		(86)	(87)
Net change in benefit obligations		85	92
Obligations at end of year		1,590	1,505	1,413
Pension Benefit Plans | Non-U.S.
Changes in the pension and postretirement benefit obligations
Obligations at beginning of year		1,150	1,022
Change in benefit obligations:
Service cost		13	12	15
Interest cost		26	33	32
Actuarial (gain) loss		67	116
Settlements		(63)	(44)
Acquisitions (Divestiture)		(56)	30
Participant contributions		1	1
Benefit payments		(51)	(37)
Other		6	(6)
Foreign currency translation		34	23
Net change in benefit obligations		(23)	128
Obligations at end of year		1,127	1,150	1,022
Other Post-retirement Benefits | U.S.
Changes in the pension and postretirement benefit obligations
Obligations at beginning of year		72	74
Change in benefit obligations:
Interest cost		2	4	3
Actuarial (gain) loss		14	3
Benefit payments		(11)	(9)
Other		(39)
Net change in benefit obligations	$ 39	(34)	(2)
Obligations at end of year		38	72	74
Other Post-retirement Benefits | Non-U.S.
Changes in the pension and postretirement benefit obligations
Obligations at beginning of year		71	80
Change in benefit obligations:
Service cost		2	1	1
Interest cost		2	3	3
Actuarial (gain) loss		5	(15)
Benefit payments		(2)	(2)
Foreign currency translation		2	4
Net change in benefit obligations		9	(9)
Obligations at end of year		$ 80	$ 71	$ 80