Pension, Other Postretirement Benefits and Savings Plans - Benefit Costs and Amounts Recognized in Other Comprehensive (Income) Loss (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2020	Dec. 31, 2019	Dec. 31, 2018
Other Postretirement Benefits
Benefits cost (credit):
Service cost	$ 2	$ 2	$ 3
Interest cost	8	11	12
Amortization of prior service cost (credit)	(9)	(9)	(8)
Amortization of net losses	4	3	4
Net periodic cost	5	7	11
Net curtailments/settlements /termination benefits	(4)
Total benefits cost	1	7	11
Recognized in other comprehensive (income) loss before tax and minority:
Prior service cost (credit) from plan amendments			(16)
Increase (decrease) in net actuarial losses	5	6	(14)
Amortization of prior service (cost) credit in net periodic cost	9	9	8
Amortization of net losses in net periodic cost	(4)	(3)	(5)
Immediate recognition of prior service cost and unrecognized gains and losses due to curtailments, settlements, and divestitures	6	2
Total recognized in other comprehensive (income) loss before tax and minority	16	14	(27)
Total recognized in total benefits cost and other comprehensive (income) loss before tax and minority	17	21	(16)
United States | Pension Plan
Benefits cost (credit):
Service cost	4	3	4
Interest cost	126	173	157
Expected return on plan assets	(193)	(223)	(219)
Amortization of net losses	109	112	112
Net periodic cost	46	65	54
Net curtailments/settlements /termination benefits	31	8	8
Total benefits cost	77	73	62
Recognized in other comprehensive (income) loss before tax and minority:
Increase (decrease) in net actuarial losses	108	4	14
Amortization of net losses in net periodic cost	(109)	(112)	(112)
Immediate recognition of prior service cost and unrecognized gains and losses due to curtailments, settlements, and divestitures	(26)	(5)	(11)
Total recognized in other comprehensive (income) loss before tax and minority	(27)	(113)	(109)
Total recognized in total benefits cost and other comprehensive (income) loss before tax and minority	50	(40)	(47)
United States | Other Postretirement Benefits
Benefits cost (credit):
Total benefits cost	1	3	4
Non-U.S. | Pension Plan
Benefits cost (credit):
Service cost	30	26	28
Interest cost	56	69	69
Expected return on plan assets	(54)	(59)	(70)
Amortization of prior service cost (credit)	1	2
Amortization of net losses	38	29	29
Net periodic cost	71	67	56
Net curtailments/settlements /termination benefits	(4)	3	13
Total benefits cost	67	70	69
Recognized in other comprehensive (income) loss before tax and minority:
Prior service cost (credit) from plan amendments	3	(2)	31
Increase (decrease) in net actuarial losses	(100)	201	(18)
Amortization of prior service (cost) credit in net periodic cost	(2)	(2)
Amortization of net losses in net periodic cost	(38)	(29)	(30)
Immediate recognition of prior service cost and unrecognized gains and losses due to curtailments, settlements, and divestitures	(9)	(3)	(14)
Total recognized in other comprehensive (income) loss before tax and minority	(146)	165	(31)
Total recognized in total benefits cost and other comprehensive (income) loss before tax and minority	(79)	235	38
Non-U.S. | Other Postretirement Benefits
Benefits cost (credit):
Total benefits cost	$ 0	$ 4	$ 7