Insurance Liabilities - Policyholder contract deposit (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2023	Dec. 31, 2022	Dec. 31, 2021	Jan. 01, 2021
Policyholder Account Balance [Roll Forward]
Legacy insurance lines ceded to Fortitude Re	$ 161,979	$ 155,984		$ 148,223
Life and Retirement
Policyholder Account Balance [Roll Forward]
Policyholder contract deposits account balance, beginning of year	158,494	152,809	$ 148,924
Issuances	29,029	23,348	21,947
Policy charges	(2,972)	(3,036)	(3,005)
Surrenders and withdrawals	(23,406)	(15,042)	(15,037)
Benefit payments	(9,274)	(7,666)	(8,927)
Net transfers from (to) separate account	7,117	4,536	4,340
Interest credited	4,417	3,564	4,594
Other	3	(19)	(27)
Policyholder Contract Deposits Account Balance, end of period	163,408	158,494	152,809
Other reconciling items	(1,429)	(2,510)	(1,423)
Legacy insurance lines ceded to Fortitude Re	161,979	155,984	151,386
Cash surrender value	142,216	138,320	136,372
Life and Retirement | Individual Retirement
Policyholder Account Balance [Roll Forward]
Policyholder contract deposits account balance, beginning of year	89,554	84,097	80,012
Issuances	18,188	15,186	13,774
Policy charges	(840)	(870)	(781)
Surrenders and withdrawals	(14,025)	(8,921)	(8,863)
Benefit payments	(3,770)	(3,798)	(4,031)
Net transfers from (to) separate account	3,617	2,248	1,531
Interest credited	2,188	1,608	2,444
Other	(16)	4	11
Policyholder Contract Deposits Account Balance, end of period	94,896	89,554	84,097
Other reconciling items	(1,429)	(2,136)	(1,289)
Legacy insurance lines ceded to Fortitude Re	$ 93,467	$ 87,418	$ 82,808
Weighted average crediting rate	2.68%	2.43%	2.42%
Cash surrender value	$ 88,685	$ 83,278	$ 79,787
Life and Retirement | Group Retirement
Policyholder Account Balance [Roll Forward]
Policyholder contract deposits account balance, beginning of year	43,395	43,902	43,406
Issuances	5,352	4,946	5,146
Policy charges	(477)	(462)	(523)
Surrenders and withdrawals	(8,310)	(5,712)	(5,795)
Benefit payments	(2,518)	(2,528)	(2,329)
Net transfers from (to) separate account	2,705	2,149	2,750
Interest credited	1,141	1,100	1,249
Other	11	0	(2)
Policyholder Contract Deposits Account Balance, end of period	41,299	43,395	43,902
Other reconciling items	(230)	(319)	(259)
Legacy insurance lines ceded to Fortitude Re	$ 41,069	$ 43,076	$ 43,643
Weighted average crediting rate	2.91%	2.77%	2.79%
Cash surrender value	$ 40,210	$ 41,831	$ 43,359
Life and Retirement | Life Insurance
Policyholder Account Balance [Roll Forward]
Policyholder contract deposits account balance, beginning of year	10,224	10,183	10,012
Issuances	1,632	1,674	1,702
Policy charges	(1,524)	(1,570)	(1,567)
Surrenders and withdrawals	(256)	(211)	(212)
Benefit payments	(281)	(216)	(245)
Net transfers from (to) separate account	3	(5)	(2)
Interest credited	413	377	447
Other	20	(8)	48
Policyholder Contract Deposits Account Balance, end of period	10,231	10,224	10,183
Other reconciling items	208	34	117
Legacy insurance lines ceded to Fortitude Re	$ 10,439	$ 10,258	$ 10,300
Weighted average crediting rate	4.41%	4.29%	4.28%
Cash surrender value	$ 9,026	$ 8,866	$ 8,826
Life and Retirement | Institutional Markets
Policyholder Account Balance [Roll Forward]
Policyholder contract deposits account balance, beginning of year	11,734	10,804	11,351
Issuances	3,813	1,494	1,272
Policy charges	(67)	(69)	(65)
Surrenders and withdrawals	(722)	(134)	(91)
Benefit payments	(2,405)	(775)	(1,948)
Net transfers from (to) separate account	792	144	61
Interest credited	507	301	263
Other	(3)	(31)	(39)
Policyholder Contract Deposits Account Balance, end of period	13,649	11,734	10,804
Other reconciling items	93	(16)	165
Legacy insurance lines ceded to Fortitude Re	$ 13,742	$ 11,718	$ 10,969
Weighted average crediting rate	4.08%	2.71%	2.41%
Cash surrender value	$ 2,583	$ 2,537	$ 2,520
Life and Retirement | Other
Policyholder Account Balance [Roll Forward]
Policyholder contract deposits account balance, beginning of year	3,587	3,823	4,143
Issuances	44	48	53
Policy charges	(64)	(65)	(69)
Surrenders and withdrawals	(93)	(64)	(76)
Benefit payments	(300)	(349)	(374)
Net transfers from (to) separate account	0	0	0
Interest credited	168	178	191
Other	(9)	16	(45)
Policyholder Contract Deposits Account Balance, end of period	3,333	3,587	3,823
Other reconciling items	(71)	(73)	(157)
Legacy insurance lines ceded to Fortitude Re	$ 3,262	$ 3,514	$ 3,666
Weighted average crediting rate	4.99%	4.91%	4.92%
Cash surrender value	$ 1,712	$ 1,808	$ 1,880
Life and Retirement | Other Operations
Policyholder Account Balance [Roll Forward]
Other reconciling items	$ 71	$ 75	$ 158