Employee Benefits - Schedule of funded status of the plans reconciled to the amount reported in the balance sheets (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021
U.S. Plans | Pension
Change in projected benefit obligation:
Benefit obligation, beginning of year	$ 3,475	$ 4,795
Service cost	5	5	$ 5
Interest cost	168	109	92
Actuarial gain (loss)	75	(1,082)
AIG assets	(16)	(19)
Plan assets	(171)	(174)
Plan amendment	0	0
Settlements	(234)	(157)
Foreign exchange effect	0	0
Other	(1)	(2)
Projected benefit obligation, end of year	3,301	3,475	4,795
Change in plan assets:
Fair value of plan assets, beginning of year	3,345	4,746
Actual return on plan assets, net of expenses	288	(1,070)
AIG contributions	16	19
Settlements	(234)	(157)
Foreign exchange effect	0	0
Fair value of plan assets, end of year	3,228	3,345	4,746
Funded status, end of year	(73)	(130)
Amounts recognized in the balance sheet:
Assets	110	55
Liabilities	(183)	(185)
Total amounts recognized	(73)	(130)
Pre-tax amounts recognized in AOCI:
Net gain (loss)	(1,142)	(1,279)
Prior service (cost) credit	0	0
Total amounts recognized	(1,142)	(1,279)
U.S. Plans | Pension | Defined Benefit Plan, Unfunded Plan
Change in projected benefit obligation:
Benefit obligation, beginning of year	186
Projected benefit obligation, end of year	184	186
U.S. Plans | Postretirement benefit plans
Change in projected benefit obligation:
Benefit obligation, beginning of year	131	174
Service cost	1	1	1
Interest cost	6	4	3
Actuarial gain (loss)	3	(36)
AIG assets	(12)	(12)
Plan assets	0	0
Plan amendment	0	0
Settlements	0	0
Foreign exchange effect	0	0
Other	0	0
Projected benefit obligation, end of year	129	131	174
Change in plan assets:
Fair value of plan assets, beginning of year	0	0
Actual return on plan assets, net of expenses	0	0
AIG contributions	12	12
Settlements	0	0
Foreign exchange effect	0	0
Fair value of plan assets, end of year	0	0	0
Funded status, end of year	(129)	(131)
Amounts recognized in the balance sheet:
Assets	0	0
Liabilities	(129)	(131)
Total amounts recognized	(129)	(131)
Pre-tax amounts recognized in AOCI:
Net gain (loss)	31	39
Prior service (cost) credit	0	0
Total amounts recognized	31	39
Foreign Plan | Pension
Change in projected benefit obligation:
Benefit obligation, beginning of year	826	1,157
Service cost	16	18	21
Interest cost	20	10	9
Actuarial gain (loss)	(8)	(183)
AIG assets	(10)	(8)
Plan assets	(31)	(26)
Plan amendment	(1)	1
Settlements	(17)	(3)
Foreign exchange effect	9	(139)
Other	0	(1)
Projected benefit obligation, end of year	804	826	1,157
Change in plan assets:
Fair value of plan assets, beginning of year	731	996
Actual return on plan assets, net of expenses	15	(133)
AIG contributions	47	42
Settlements	(23)	(3)
Foreign exchange effect	5	(137)
Fair value of plan assets, end of year	734	731	996
Funded status, end of year	(70)	(95)
Amounts recognized in the balance sheet:
Assets	97	78
Liabilities	(167)	(173)
Total amounts recognized	(70)	(95)
Pre-tax amounts recognized in AOCI:
Net gain (loss)	(79)	(70)
Prior service (cost) credit	(21)	(25)
Total amounts recognized	(100)	(95)
Foreign Plan | Pension | Defined Benefit Plan, Unfunded Plan
Change in projected benefit obligation:
Benefit obligation, beginning of year	143
Projected benefit obligation, end of year	140	143
Foreign Plan | Postretirement benefit plans
Change in projected benefit obligation:
Benefit obligation, beginning of year	32	47
Service cost	0	0	1
Interest cost	2	1	2
Actuarial gain (loss)	(2)	(14)
AIG assets	(1)	(1)
Plan assets	0	0
Plan amendment	0	0
Settlements	0	0
Foreign exchange effect	0	(1)
Other	0	0
Projected benefit obligation, end of year	31	32	47
Change in plan assets:
Fair value of plan assets, beginning of year	0	0
Actual return on plan assets, net of expenses	0	0
AIG contributions	1	1
Settlements	0	0
Foreign exchange effect	0	0
Fair value of plan assets, end of year	0	0	$ 0
Funded status, end of year	(31)	(32)
Amounts recognized in the balance sheet:
Assets	0	0
Liabilities	(31)	(32)
Total amounts recognized	(31)	(32)
Pre-tax amounts recognized in AOCI:
Net gain (loss)	23	24
Prior service (cost) credit	1	1
Total amounts recognized	$ 24	$ 25