Postretirement benefits Components of net periodic benefit costs (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2022	Sep. 30, 2021	Sep. 30, 2022	Sep. 30, 2021
Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	$ 1	$ 1	$ 3	$ 3
Non-service (benefit) cost	(55)	(50)	(164)	(153)
Net periodic benefit cost (benefit)	(54)	(49)	(161)	(150)
Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	0	1	0	1
Interest cost	0	1	1	1
Expected return on plan assets	0	(1)	(1)	(1)
Defined Benefit Plan, Amortization of Gain (Loss)	0	0	0	0
Amortization of prior service cost	0	0	0	(26)
Settlements	0	0	0	0
Non-service (benefit) cost	0	0	0	(26)
Net periodic benefit cost (benefit)	0	1	0	(25)
Losses and loss expenses | Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	0	0	0	0
Non-service (benefit) cost	(5)	(5)	(15)	(14)
Losses and loss expenses | Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	0	0	0	0
Non-service (benefit) cost	0	0	0	(3)
Administrative Expense | Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	1	1	3	3
Non-service (benefit) cost	(50)	(45)	(149)	(139)
Administrative Expense | Other Postretirement Benefits Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	0	1	0	1
Non-service (benefit) cost	0	0	0	(23)
Foreign Plan [Member] | Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	1	1	3	3
Interest cost	5	5	17	14
Expected return on plan assets	(11)	(10)	(33)	(32)
Defined Benefit Plan, Amortization of Gain (Loss)	0	0	0	2
Amortization of prior service cost	0	0	0	0
Settlements	0	0	0	0
Non-service (benefit) cost	(6)	(5)	(16)	(16)
Net periodic benefit cost (benefit)	(5)	(4)	(13)	(13)
UNITED STATES | Pension Plan [Member]
Defined Benefit Plans and Other Postretirement Benefit Plans
Service cost	0	0	0	0
Interest cost	21	18	64	53
Expected return on plan assets	(70)	(64)	(212)	(191)
Defined Benefit Plan, Amortization of Gain (Loss)	0	0	0	0
Amortization of prior service cost	0	0	0	0
Settlements	0	1	0	1
Non-service (benefit) cost	(49)	(45)	(148)	(137)
Net periodic benefit cost (benefit)	$ (49)	$ (45)	$ (148)	$ (137)