Unpaid losses and loss expenses Unpaid Losses and loss expenses, claims development (Cumulative Net incurred Loss and Allocated Loss Adjustment Expense) (Details) $ in Millions	Dec. 31, 2023 USD ($)	Dec. 31, 2022 USD ($)	Dec. 31, 2021 USD ($)	Dec. 31, 2020 USD ($)	Dec. 31, 2019 USD ($)	Dec. 31, 2018 USD ($)	Dec. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	$ 60,209
North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	12,508
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	5,289
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	10,159
North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	39,558
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	20,402
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	21,092
North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	6,453
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	4,085
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	2,596
North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	22,885
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	19,669
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	3,203
North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	28,150
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	24,647
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	3,550
Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	14,455
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	6,838
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	8,157
Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	21,925
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	18,549
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	3,515
Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	2,685
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	1,724
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	1,240
Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	2,481
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	2,081
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net	411
Short-duration Insurance Contracts, Accident Year 2014 [Member] | North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	983	$ 1,007	$ 1,037	$ 1,073	$ 1,100	$ 1,163	$ 1,215	$ 1,217	$ 1,201	$ 1,207
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	236
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 649	634	617	599	566	532	484	410	295	113
Cumulative Number of Reported Claims	45,000
Short-duration Insurance Contracts, Accident Year 2014 [Member] | North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 3,134	3,142	3,192	3,340	3,463	3,649	3,710	3,667	3,578	3,528
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	237
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,802	2,753	2,669	2,580	2,439	2,199	1,801	1,248	679	164
Cumulative Number of Reported Claims	24,000
Short-duration Insurance Contracts, Accident Year 2014 [Member] | North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 530	526	530	538	538	554	595	580	582	594
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	9
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 517	513	508	500	473	454	391	317	220	80
Cumulative Number of Reported Claims	17,000
Short-duration Insurance Contracts, Accident Year 2014 [Member] | North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,554	1,544	1,545	1,552	1,544	1,543	1,552	1,573	1,655	1,635
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	0
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,551	1,552	1,552	1,547	1,540	1,525	1,499	1,478	1,368	816
Cumulative Number of Reported Claims	483,000
Short-duration Insurance Contracts, Accident Year 2014 [Member] | North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,130	2,133	2,134	2,135	2,140	2,153	2,139	2,186	2,199	2,198
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	6
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,121	2,119	2,116	2,109	2,100	2,073	2,028	1,919	1,759	1,306
Cumulative Number of Reported Claims	144,000
Short-duration Insurance Contracts, Accident Year 2014 [Member] | Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,089	1,106	1,103	1,093	1,129	1,210	1,290	1,271	1,264	1,196
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	46
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 934	894	865	823	761	681	571	444	275	105
Cumulative Number of Reported Claims	38,000
Short-duration Insurance Contracts, Accident Year 2014 [Member] | Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,693	1,698	1,706	1,712	1,719	1,729	1,763	1,775	1,828	1,764
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	3
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,680	1,678	1,684	1,677	1,662	1,649	1,619	1,560	1,359	721
Cumulative Number of Reported Claims	533,000
Short-duration Insurance Contracts, Accident Year 2014 [Member] | Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 326	326	327	327	344	340	339	336	331	330
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	6
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	304	298	293	284	274	263	247	216	183	91
Short-duration Insurance Contracts, Accident Year 2014 [Member] | Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	169	169	170	172	173	174	176	173	174	158
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	1
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	166	166	165	165	163	161	156	146	124	$ 63
Short-duration Insurance Contracts, Accident Year 2015 [Member] | North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	1,057	1,092	1,128	1,154	1,217	1,279	1,276	1,259	1,282
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	286
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 665	645	628	606	564	501	418	301	116
Cumulative Number of Reported Claims	50,000
Short-duration Insurance Contracts, Accident Year 2015 [Member] | North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 3,613	3,569	3,701	3,727	3,934	3,967	3,810	3,701	3,552
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	358
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 3,079	2,921	2,743	2,527	2,287	1,852	1,203	604	138
Cumulative Number of Reported Claims	27,000
Short-duration Insurance Contracts, Accident Year 2015 [Member] | North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 456	457	462	454	457	514	500	469	486
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	18
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 431	423	411	394	370	304	214	137	47
Cumulative Number of Reported Claims	15,000
Short-duration Insurance Contracts, Accident Year 2015 [Member] | North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,589	1,592	1,587	1,585	1,600	1,633	1,645	1,740	1,731
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	2
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,583	1,582	1,583	1,570	1,567	1,552	1,484	1,339	724
Cumulative Number of Reported Claims	545,000
Short-duration Insurance Contracts, Accident Year 2015 [Member] | North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,558	2,561	2,559	2,562	2,556	2,536	2,553	2,543	2,488
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	5
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,542	2,535	2,526	2,501	2,472	2,385	2,264	2,078	1,495
Cumulative Number of Reported Claims	148,000
Short-duration Insurance Contracts, Accident Year 2015 [Member] | Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,186	1,187	1,171	1,186	1,244	1,262	1,239	1,209	1,118
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	97
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 969	938	906	830	753	637	465	267	80
Cumulative Number of Reported Claims	40,000
Short-duration Insurance Contracts, Accident Year 2015 [Member] | Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,870	1,875	1,874	1,892	1,900	1,916	1,947	1,973	1,855
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	8
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,839	1,839	1,836	1,819	1,790	1,769	1,691	1,469	812
Cumulative Number of Reported Claims	556,000
Short-duration Insurance Contracts, Accident Year 2015 [Member] | Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 307	308	305	301	305	297	296	286	281
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	9
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	281	273	264	247	230	215	190	158	89
Short-duration Insurance Contracts, Accident Year 2015 [Member] | Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	154	154	154	156	151	158	158	152	144
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	1
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	151	150	150	148	144	140	130	102	$ 56
Short-duration Insurance Contracts, Accident Year 2016 [Member] | North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	1,162	1,177	1,206	1,269	1,378	1,383	1,361	1,366
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	354
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 683	653	621	584	529	452	326	122
Cumulative Number of Reported Claims	51,000
Short-duration Insurance Contracts, Accident Year 2016 [Member] | North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 3,660	3,756	3,765	3,793	3,797	3,685	3,588	3,527
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	375
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,982	2,820	2,593	2,332	1,973	1,334	662	171
Cumulative Number of Reported Claims	27,000
Short-duration Insurance Contracts, Accident Year 2016 [Member] | North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 473	469	479	480	523	527	501	503
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	20
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 437	424	398	374	323	246	145	52
Cumulative Number of Reported Claims	16,000
Short-duration Insurance Contracts, Accident Year 2016 [Member] | North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,822	1,820	1,824	1,811	1,775	1,794	1,884	1,904
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	23
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,790	1,789	1,778	1,754	1,726	1,650	1,499	844
Cumulative Number of Reported Claims	650,000
Short-duration Insurance Contracts, Accident Year 2016 [Member] | North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,467	2,466	2,458	2,464	2,476	2,538	2,529	2,433
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	10
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,440	2,422	2,391	2,364	2,308	2,205	2,046	1,449
Cumulative Number of Reported Claims	154,000
Short-duration Insurance Contracts, Accident Year 2016 [Member] | Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,283	1,271	1,337	1,328	1,338	1,311	1,246	1,150
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	93
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,003	979	857	766	648	505	306	120
Cumulative Number of Reported Claims	42,000
Short-duration Insurance Contracts, Accident Year 2016 [Member] | Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,943	1,955	1,957	1,926	1,921	1,942	1,955	1,959
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	29
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,890	1,887	1,881	1,872	1,847	1,779	1,592	966
Cumulative Number of Reported Claims	568,000
Short-duration Insurance Contracts, Accident Year 2016 [Member] | Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 250	244	239	239	230	231	223	219
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	11
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	217	206	190	173	157	141	112	57
Short-duration Insurance Contracts, Accident Year 2016 [Member] | Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	181	181	181	184	187	185	182	177
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	1
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	177	176	175	172	166	156	129	$ 56
Short-duration Insurance Contracts, Accident Year 2017 [Member] | North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	1,121	1,176	1,376	1,393	1,399	1,380	1,412
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	402
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 626	601	564	516	437	313	120
Cumulative Number of Reported Claims	50,000
Short-duration Insurance Contracts, Accident Year 2017 [Member] | North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 3,492	3,434	3,545	3,623	3,573	3,491	3,316
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	603
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,627	2,322	2,000	1,698	1,160	616	161
Cumulative Number of Reported Claims	26,000
Short-duration Insurance Contracts, Accident Year 2017 [Member] | North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 602	590	604	616	577	565	531
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	16
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 539	496	446	381	312	175	66
Cumulative Number of Reported Claims	17,000
Short-duration Insurance Contracts, Accident Year 2017 [Member] | North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,508	2,522	2,512	2,520	2,503	2,603	2,699
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	43
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,449	2,430	2,406	2,392	2,301	2,083	977
Cumulative Number of Reported Claims	764,000
Short-duration Insurance Contracts, Accident Year 2017 [Member] | North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 3,011	3,001	2,992	2,991	2,995	3,062	3,028
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	20
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,971	2,930	2,864	2,793	2,662	2,514	1,694
Cumulative Number of Reported Claims	163,000
Short-duration Insurance Contracts, Accident Year 2017 [Member] | Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,296	1,331	1,296	1,331	1,284	1,237	1,140
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	151
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 995	940	812	653	499	299	91
Cumulative Number of Reported Claims	43,000
Short-duration Insurance Contracts, Accident Year 2017 [Member] | Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,115	2,149	2,151	2,126	2,145	2,157	2,114
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	(6)
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,091	2,114	2,055	2,013	1,940	1,772	1,010
Cumulative Number of Reported Claims	577,000
Short-duration Insurance Contracts, Accident Year 2017 [Member] | Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 221	214	214	213	216	211	209
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	6
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	185	173	153	138	120	99	46
Short-duration Insurance Contracts, Accident Year 2017 [Member] | Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	454	455	453	449	451	421	395
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	7
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	439	433	426	413	400	321	$ 191
Short-duration Insurance Contracts, Accident Year 2018 [Member] | North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	1,221	1,384	1,385	1,380	1,361	1,359
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	435
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 641	597	528	451	329	130
Cumulative Number of Reported Claims	51,000
Short-duration Insurance Contracts, Accident Year 2018 [Member] | North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 3,915	3,900	3,820	3,688	3,485	3,368
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	672
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,782	2,335	1,773	1,301	753	189
Cumulative Number of Reported Claims	28,000
Short-duration Insurance Contracts, Accident Year 2018 [Member] | North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 606	575	579	574	563	535
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	9
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 532	472	365	270	169	74
Cumulative Number of Reported Claims	17,000
Short-duration Insurance Contracts, Accident Year 2018 [Member] | North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,160	2,170	2,161	2,169	2,234	2,047
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	11
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,137	2,113	2,068	2,012	1,821	1,025
Cumulative Number of Reported Claims	904,000
Short-duration Insurance Contracts, Accident Year 2018 [Member] | North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 3,120	3,131	3,110	3,095	3,030	3,002
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	45
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 3,037	2,971	2,857	2,699	2,542	1,922
Cumulative Number of Reported Claims	170,000
Short-duration Insurance Contracts, Accident Year 2018 [Member] | Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,323	1,345	1,389	1,346	1,286	1,236
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	202
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 881	727	608	470	312	105
Cumulative Number of Reported Claims	44,000
Short-duration Insurance Contracts, Accident Year 2018 [Member] | Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,051	2,062	2,093	2,119	2,156	2,068
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	42
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,950	1,940	1,924	1,858	1,664	960
Cumulative Number of Reported Claims	613,000
Short-duration Insurance Contracts, Accident Year 2018 [Member] | Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 255	248	245	249	242	239
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	9
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	194	168	146	123	94	40
Short-duration Insurance Contracts, Accident Year 2018 [Member] | Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	282	289	284	288	286	278
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	2
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	274	272	267	264	248	$ 94
Short-Duration Insurance Contract, Accident Year 2019 [Member] | North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	1,406	1,409	1,400	1,384	1,391
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	611
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 640	575	467	341	143
Cumulative Number of Reported Claims	48,000
Short-Duration Insurance Contract, Accident Year 2019 [Member] | North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 4,057	4,050	3,858	3,620	3,446
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	1,135
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,387	1,888	1,245	669	175
Cumulative Number of Reported Claims	29,000
Short-Duration Insurance Contract, Accident Year 2019 [Member] | North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 756	744	686	636	606
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	40
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 619	465	318	189	70
Cumulative Number of Reported Claims	17,000
Short-Duration Insurance Contract, Accident Year 2019 [Member] | North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,921	1,944	1,954	2,031	2,046
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	13
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,883	1,856	1,800	1,672	1,028
Cumulative Number of Reported Claims	1,044,000
Short-Duration Insurance Contract, Accident Year 2019 [Member] | North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,957	2,978	2,986	2,985	2,949
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	48
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,823	2,718	2,611	2,431	1,664
Cumulative Number of Reported Claims	157,000
Short-Duration Insurance Contract, Accident Year 2019 [Member] | Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,336	1,382	1,395	1,373	1,307
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	311
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 729	648	444	316	118
Cumulative Number of Reported Claims	42,000
Short-Duration Insurance Contract, Accident Year 2019 [Member] | Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,043	2,047	2,059	2,119	2,100
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	(12)
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,959	1,926	1,861	1,674	1,019
Cumulative Number of Reported Claims	632,000
Short-Duration Insurance Contract, Accident Year 2019 [Member] | Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 233	236	237	242	233
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	20
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	161	138	115	89	39
Short-Duration Insurance Contract, Accident Year 2019 [Member] | Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	116	120	125	129	130
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	3
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	104	102	94	80	$ 35
Short-Duration Insurance Contract, Accident Year 2020 | North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	1,408	1,409	1,388	1,367
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	756
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 466	390	282	111
Cumulative Number of Reported Claims	31,000
Short-Duration Insurance Contract, Accident Year 2020 | North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 3,976	3,919	3,826	4,102
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	1,630
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,697	1,148	589	152
Cumulative Number of Reported Claims	24,000
Short-Duration Insurance Contract, Accident Year 2020 | North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 638	657	633	640
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	156
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 401	273	156	54
Cumulative Number of Reported Claims	11,000
Short-Duration Insurance Contract, Accident Year 2020 | North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,685	2,726	2,942	3,140
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	62
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,545	2,466	2,260	1,390
Cumulative Number of Reported Claims	1,126,000
Short-Duration Insurance Contract, Accident Year 2020 | North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,582	2,626	2,627	2,922
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	96
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,363	2,223	1,990	1,331
Cumulative Number of Reported Claims	123,000
Short-Duration Insurance Contract, Accident Year 2020 | Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,535	1,523	1,606	1,684
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	765
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 530	429	273	102
Cumulative Number of Reported Claims	35,000
Short-Duration Insurance Contract, Accident Year 2020 | Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,116	2,171	2,301	2,437
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	87
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,908	1,792	1,646	1,036
Cumulative Number of Reported Claims	534,000
Short-Duration Insurance Contract, Accident Year 2020 | Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 237	237	246	242
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	42
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	147	123	98	41
Short-Duration Insurance Contract, Accident Year 2020 | Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	279	277	253	209
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	22
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	232	215	177	$ 62
Short-Duration Insurance Contract, Accident Year 2021 | North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	1,372	1,330	1,348
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	708
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 458	331	120
Cumulative Number of Reported Claims	35,000
Short-Duration Insurance Contract, Accident Year 2021 | North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 4,441	4,349	4,315
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	2,589
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,200	609	174
Cumulative Number of Reported Claims	25,000
Short-Duration Insurance Contract, Accident Year 2021 | North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 747	710	675
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	254
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 293	176	60
Cumulative Number of Reported Claims	13,000
Short-Duration Insurance Contract, Accident Year 2021 | North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,628	2,824	2,941
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	158
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,322	2,100	1,085
Cumulative Number of Reported Claims	863,000
Short-Duration Insurance Contract, Accident Year 2021 | North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,964	2,877	3,027
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	209
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,582	2,368	1,583
Cumulative Number of Reported Claims	131,000
Short-Duration Insurance Contract, Accident Year 2021 | Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,691	1,668	1,619
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	987
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 434	271	111
Cumulative Number of Reported Claims	36,000
Short-Duration Insurance Contract, Accident Year 2021 | Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,322	2,437	2,524
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	60
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,025	1,750	982
Cumulative Number of Reported Claims	542,000
Short-Duration Insurance Contract, Accident Year 2021 | Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 286	282	278
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	105
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	119	86	35
Short-Duration Insurance Contract, Accident Year 2021 | Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	354	351	340
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	23
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	307	277	$ 158
Short-Duration Insurance Contract, Accident Year 2022 | North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	1,407	1,344
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	835
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 332	131
Cumulative Number of Reported Claims	38,000
Short-Duration Insurance Contract, Accident Year 2022 | North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 4,567	4,561
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	3,371
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 649	144
Cumulative Number of Reported Claims	25,000
Short-Duration Insurance Contract, Accident Year 2022 | North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 801	782
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	367
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 235	82
Cumulative Number of Reported Claims	14,000
Short-Duration Insurance Contract, Accident Year 2022 | North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,946	3,048
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	371
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,190	1,050
Cumulative Number of Reported Claims	897,000
Short-Duration Insurance Contract, Accident Year 2022 | North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,955	3,102
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	414
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,278	1,411
Cumulative Number of Reported Claims	119,000
Short-Duration Insurance Contract, Accident Year 2022 | Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,808	1,760
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	1,217
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 284	83
Cumulative Number of Reported Claims	36,000
Short-Duration Insurance Contract, Accident Year 2022 | Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,777	2,800
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	168
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 2,088	1,168
Cumulative Number of Reported Claims	614,000
Short-Duration Insurance Contract, Accident Year 2022 | Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 296	294
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	155
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	86	39
Short-Duration Insurance Contract, Accident Year 2022 | Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	311	346
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	69
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	195	$ 74
Short-Duration Insurance Contract, Accident Year 2023 | North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	1,371
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	992
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 129
Cumulative Number of Reported Claims	33,000
Short-Duration Insurance Contract, Accident Year 2023 | North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 4,703
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	4,181
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 197
Cumulative Number of Reported Claims	26,000
Short-Duration Insurance Contract, Accident Year 2023 | North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 844
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	631
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 81
Cumulative Number of Reported Claims	11,000
Short-Duration Insurance Contract, Accident Year 2023 | North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 3,072
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	1,351
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,219
Cumulative Number of Reported Claims	756,000
Short-Duration Insurance Contract, Accident Year 2023 | North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 3,406
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	1,480
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,490
Cumulative Number of Reported Claims	93,000
Short-Duration Insurance Contract, Accident Year 2023 | Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 1,908
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	1,606
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 79
Cumulative Number of Reported Claims	32,000
Short-Duration Insurance Contract, Accident Year 2023 | Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 2,995
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	901
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	$ 1,119
Cumulative Number of Reported Claims	594,000
Short-Duration Insurance Contract, Accident Year 2023 | Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	$ 274
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	211
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	30
Short-Duration Insurance Contract, Accident Year 2023 | Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Incurred Claims and Allocated Claim Adjustment Expense, Net	181
Short-duration Insurance Contracts, Incurred but Not Reported (IBNR) Claims Liability, Net	109
Short-duration Insurance Contracts, Cumulative Paid Claims and Allocated Claim Adjustment Expense, Net	36
Accident years prior to 2014 | North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	2,940
Accident years prior to 2014 | North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	1,936
Accident years prior to 2014 | North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	228
Accident years prior to 2014 | North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	(13)
Accident years prior to 2014 | North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	47
Accident years prior to 2014 | Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	540
Accident years prior to 2014 | Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	139
Accident years prior to 2014 | Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	279
Accident years prior to 2014 | Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	11
Accident years 2014 - 2023 | North America Commercial P&C Insurance - Workers' Compensation [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	7,219
Accident years 2014 - 2023 | North America Commercial P&C Insurance - Liability [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	19,156
Accident years 2014 - 2023 | North America Commercial P&C Insurance - Other Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	2,368
Accident years 2014 - 2023 | North America Commercial P&C Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	3,216
Accident years 2014 - 2023 | North America Personal P&C Insurance [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	3,503
Accident years 2014 - 2023 | Overseas General Insurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	7,617
Accident years 2014 - 2023 | Overseas General Insurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	3,376
Accident years 2014 - 2023 | Global Reinsurance - Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	961
Accident years 2014 - 2023 | Global Reinsurance - Non-Casualty [Member]
Claims Development [Line Items]
Short-duration Insurance Contracts, Liability for Unpaid Claims and Allocated Claim Adjustment Expense, Net, Not Separately Presented	$ 400