Postretirement benefits Schedule of Allocation of Plan Assets (Details) - USD ($) $ in Millions	Dec. 31, 2023		Dec. 31, 2022		Dec. 31, 2021
Defined Benefit Plan Disclosure [Line Items]
Other investments	$ 5,527		$ 1,341
Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	69		81		$ 119
Fair Value, Recurring [Member] | Level 1
Defined Benefit Plan Disclosure [Line Items]
Other investments	589	[1]	552	[2]
Fair Value, Recurring [Member] | Level 2
Defined Benefit Plan Disclosure [Line Items]
Other investments	4,236	[1]	399	[2]
Fair Value, Recurring [Member] | Level 3
Defined Benefit Plan Disclosure [Line Items]
Other investments	0	[1]	0	[2]
Other Investments | Other Postretirement Benefits Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined Benefit Plan, Plan Assets, Amount	35		31
Investment Funds Limited Partnerships Partially Owned Investment Companies Fair Value [Member]
Defined Benefit Plan Disclosure [Line Items]
Other investments	14,078		12,355
UNITED STATES | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Other investments	634		538
Defined benefit plan, fair value of plan assets excluding measured using NAV	2,715	[3]	2,540	[4]
Defined Benefit Plan, Plan Assets, Amount	3,589		3,316		4,151
Cash, including restricted cash $172 and $115 (includes VIE balances of $117 and nil)	16		5
UNITED STATES | Pension Plan [Member] | Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	1,986	[3]	1,798	[4]
UNITED STATES | Pension Plan [Member] | Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	729	[3]	742	[4]
UNITED STATES | Pension Plan [Member] | Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	0	[3]	0	[4]
UNITED STATES | Pension Plan [Member] | Short-term investments
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	45		42
UNITED STATES | Pension Plan [Member] | Short-term investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	45		42
UNITED STATES | Pension Plan [Member] | Short-term investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	0		0
UNITED STATES | Pension Plan [Member] | Short-term investments | Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	0		0
UNITED STATES | Pension Plan [Member] | U.S. Treasury / Agency
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	556		541
UNITED STATES | Pension Plan [Member] | U.S. Treasury / Agency | Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	470		431
UNITED STATES | Pension Plan [Member] | U.S. Treasury / Agency | Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	86		110
UNITED STATES | Pension Plan [Member] | U.S. Treasury / Agency | Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	0		0
UNITED STATES | Pension Plan [Member] | Debt Security, Government, Non-US [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	637		627
UNITED STATES | Pension Plan [Member] | Debt Security, Government, Non-US [Member] | Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	0		0
UNITED STATES | Pension Plan [Member] | Debt Security, Government, Non-US [Member] | Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	637		627
UNITED STATES | Pension Plan [Member] | Debt Security, Government, Non-US [Member] | Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	0		0
UNITED STATES | Pension Plan [Member] | States, municipalities, and political subdivisions
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	6		5
UNITED STATES | Pension Plan [Member] | States, municipalities, and political subdivisions | Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	0		0
UNITED STATES | Pension Plan [Member] | States, municipalities, and political subdivisions | Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	6		5
UNITED STATES | Pension Plan [Member] | States, municipalities, and political subdivisions | Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	0		0
UNITED STATES | Pension Plan [Member] | Defined Benefit Plan, Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	1,466		1,321
UNITED STATES | Pension Plan [Member] | Defined Benefit Plan, Equity Securities [Member] | Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	1,466		1,321
UNITED STATES | Pension Plan [Member] | Defined Benefit Plan, Equity Securities [Member] | Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	0		0
UNITED STATES | Pension Plan [Member] | Defined Benefit Plan, Equity Securities [Member] | Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	0		0
UNITED STATES | Pension Plan [Member] | Defined Benefit Plan, Derivative
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	5		4
UNITED STATES | Pension Plan [Member] | Defined Benefit Plan, Derivative | Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	5		4
UNITED STATES | Pension Plan [Member] | Defined Benefit Plan, Derivative | Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	0		0
UNITED STATES | Pension Plan [Member] | Defined Benefit Plan, Derivative | Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	0		0
UNITED STATES | Investment Funds Limited Partnerships Partially Owned Investment Companies Fair Value [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Other investments	224		233
Non - U.S. | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Other investments	227		201
Defined benefit plan, fair value of plan assets excluding measured using NAV	742	[3]	721	[4]
Defined Benefit Plan, Plan Assets, Amount	986		938		$ 1,318
Non - U.S. | Pension Plan [Member] | Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	70	[3]	117	[4]
Non - U.S. | Pension Plan [Member] | Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	668	[3]	600	[4]
Non - U.S. | Pension Plan [Member] | Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	4	[3]	4	[4]
Non - U.S. | Pension Plan [Member] | Short-term investments
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	7		10
Non - U.S. | Pension Plan [Member] | Short-term investments | Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	7		10
Non - U.S. | Pension Plan [Member] | Short-term investments | Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	0		0
Non - U.S. | Pension Plan [Member] | Short-term investments | Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	0		0
Non - U.S. | Pension Plan [Member] | Debt Security, Government, Non-US [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	457		454
Non - U.S. | Pension Plan [Member] | Debt Security, Government, Non-US [Member] | Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	0		0
Non - U.S. | Pension Plan [Member] | Debt Security, Government, Non-US [Member] | Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	457		454
Non - U.S. | Pension Plan [Member] | Debt Security, Government, Non-US [Member] | Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	0		0
Non - U.S. | Pension Plan [Member] | Defined Benefit Plan, Equity Securities [Member]
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	278		257
Non - U.S. | Pension Plan [Member] | Defined Benefit Plan, Equity Securities [Member] | Level 1
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	63		107
Non - U.S. | Pension Plan [Member] | Defined Benefit Plan, Equity Securities [Member] | Level 2
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	211		146
Non - U.S. | Pension Plan [Member] | Defined Benefit Plan, Equity Securities [Member] | Level 3
Defined Benefit Plan Disclosure [Line Items]
Defined benefit plan, fair value of plan assets excluding measured using NAV	4		4
Non - U.S. | Investment Funds Limited Partnerships Partially Owned Investment Companies Fair Value [Member] | Pension Plan [Member]
Defined Benefit Plan Disclosure [Line Items]
Other investments	$ 17		$ 16

[1] Excluded from the table above are other investments of $702 million, principally policy loans at December 31, 2023 measured using NAV as a practical expedient

[2] Excluded from the table above are other investments of $390 million, principally policy loans at December 31, 2022 measured using NAV as a practical expedient. (2)Excluded from the table above are Private equities of $12,355 million at December 31, 2022 measured using NAV as a practical expedient.

[3] Excluded from the table above are $634 million and $227 million of other investments related to the U.S. Plans and Non-U.S. Plans, respectively, private equities of $224 million and $17 million in U.S. Plans and Non-U.S. Plans, respectively, measured using NAV as a practical expedient, and $16 million in cash and accrued income related to the U.S. Plans.

[4] Excluded from the table above are $538 million and $201 million of other investments related to the U.S. Plans and Non-U.S. Plans, respectively, private equities of $233 million and $16 million in U.S. Plans and Non-U.S. Plans, respectively, measured using NAV as a practical expedient, and $5 million in cash and accrued income related to the U.S. Plans.