INSURANCE LIABILITIES (Details - Undiscounted, Incurred and Paid Losses and Allocated Loss Adjustment Expenses) $ in Millions	3 Months Ended								12 Months Ended
	Dec. 31, 2017 USD ($) item	Sep. 30, 2017 USD ($)	Jun. 30, 2017 USD ($)	Mar. 31, 2017 USD ($)	Dec. 31, 2016 USD ($)	Sep. 30, 2016 USD ($)	Jun. 30, 2016 USD ($)	Mar. 31, 2016 USD ($)	Dec. 31, 2017 USD ($) item	Dec. 31, 2016 USD ($)	Dec. 31, 2015 USD ($)	Dec. 31, 2014 USD ($)	Dec. 31, 2013 USD ($)	Dec. 31, 2012 USD ($)	Dec. 31, 2011 USD ($)	Dec. 31, 2010 USD ($)	Dec. 31, 2009 USD ($)	Dec. 31, 2008 USD ($)
Claims Development [Line Items]
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									$ 1,565	$ 5,788	$ 4,119
Reserve strengthening charges	$ 212	$ 901	$ 391	$ 61	$ 5,574	$ 273	$ 7	$ (66)
Liabilities for losses and loss adjustment expenses, net of reinsurance	51,685				61,545				51,685	61,545	60,603	$ 61,612
U.S. Workers Compensation
Claims Development [Line Items]
Reserve strengthening charges									(31)	1,900	234
Total	24,876								24,876
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	16,580								16,580
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	3,867								3,867
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	12,163								12,163
U.S. Excess Casualty
Claims Development [Line Items]
Reserve strengthening charges									254	1,100	1,400
Total	13,410								13,410
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	7,120								7,120
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	1,649								1,649
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	7,939								7,939
U.S. Other Casualty
Claims Development [Line Items]
Reserve strengthening charges									216	1,600	1,400
Total	21,565								21,565
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	15,521								15,521
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	1,406								1,406
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	7,450								7,450
U.S. Financial Lines
Claims Development [Line Items]
Reserve strengthening charges									345	306	502
Total	18,500								18,500
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	12,615								12,615
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	88								88
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	5,973								5,973
U.S. Property and Special Risks
Claims Development [Line Items]
Reserve strengthening charges									115	396	(132)
Total	27,032								27,032
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	21,589								21,589
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	318								318
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	5,761								5,761
U.S. Personal Insurance
Claims Development [Line Items]
Reserve strengthening charges									16	(32)	(69)
Total	17,538								17,538
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	16,053								16,053
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	(65)								(65)
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	1,420								1,420
Europe Casualty and Financial Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	15,357								15,357
Reserve strengthening charges									507	320	142
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	8,965								8,965
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	594								594
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	6,986								6,986
Europe Property and Special Risks
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	8,986								8,986
Reserve strengthening charges									157	11	4
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	6,971								6,971
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	7								7
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	2,022								2,022
Europe and Japan Personal Insurance
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	28,468								28,468
Reserve strengthening charges									(58)	(82)	15
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	26,161								26,161
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	41								41
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	2,348								2,348
U.S. Run-Off Long Tail Insurance Lines
Claims Development [Line Items]
Reserve strengthening charges									(30)	390
Total	5,597								5,597
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	3,830								3,830
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	3,616								3,616
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	5,383								5,383
Prior to 2008
Claims Development [Line Items]
Reserve strengthening charges									424	1,840	1,848
Prior to 2008 | U.S. Workers Compensation
Claims Development [Line Items]
Reserve strengthening charges									4	1,009	100
Prior to 2008 | U.S. Excess Casualty
Claims Development [Line Items]
Reserve strengthening charges									141	107	450
Prior to 2008 | U.S. Other Casualty
Claims Development [Line Items]
Reserve strengthening charges									10	338	440
Prior to 2008 | U.S. Financial Lines
Claims Development [Line Items]
Reserve strengthening charges									(44)	31	191
Prior to 2008 | U.S. Property and Special Risks
Claims Development [Line Items]
Reserve strengthening charges									12	12	26
Prior to 2008 | U.S. Personal Insurance
Claims Development [Line Items]
Reserve strengthening charges									5	(13)	33
Prior to 2008 | Europe Casualty and Financial Lines
Claims Development [Line Items]
Reserve strengthening charges									169	(6)	(2)
Prior to 2008 | Europe Property and Special Risks
Claims Development [Line Items]
Reserve strengthening charges									(5)	1	(1)
Prior to 2008 | Europe and Japan Personal Insurance
Claims Development [Line Items]
Reserve strengthening charges									1	(5)	1
Prior to 2008 | U.S. Run-Off Long Tail Insurance Lines
Claims Development [Line Items]
Reserve strengthening charges									(46)	363	621
Prior to 2008 | All Other
Claims Development [Line Items]
Reserve strengthening charges									177	3	(11)
2008 | U.S. Workers Compensation
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	4,536				4,547				4,536	4,547	4,398	4,385	$ 4,398	$ 4,471	$ 4,425	$ 4,422	$ 4,184	$ 4,114
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(11)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 448								$ 448
Cumulative Number of Reported Claims | item	198,852								198,852
Incurred Impact of Adverse Development Reinsurance Agreement	$ (416)								$ (416)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	4,120								4,120
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	32								32
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	3,789				3,707				3,789	3,707	3,609	3,476	3,272	3,044	2,655	2,252	1,678	785
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2008 | U.S. Excess Casualty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,658				1,635				1,658	1,635	1,662	1,714	1,875	1,819	1,933	2,146	1,968	1,948
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									23
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 188								$ 188
Cumulative Number of Reported Claims | item	4,662								4,662
Incurred Impact of Adverse Development Reinsurance Agreement	$ (176)								$ (176)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,482								1,482
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	12								12
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,364				1,226				1,364	1,226	1,172	1,061	954	842	667	439	97	11
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2008 | U.S. Other Casualty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	3,175				3,193				3,175	3,193	3,154	3,087	2,983	2,981	2,901	2,837	2,773	2,957
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(18)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 204								$ 204
Cumulative Number of Reported Claims | item	117,484								117,484
Incurred Impact of Adverse Development Reinsurance Agreement	$ (104)								$ (104)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	3,071								3,071
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	100								100
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	2,895				2,835				2,895	2,835	2,731	2,586	2,396	2,119	1,771	1,251	791	277
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2008 | U.S. Financial Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,106				2,096				2,106	2,096	2,066	1,933	1,897	1,961	1,847	2,017	2,045	1,871
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									10
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 36								$ 36
Cumulative Number of Reported Claims | item	21,719								21,719
Incurred Impact of Adverse Development Reinsurance Agreement	$ (21)								$ (21)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	2,085								2,085
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	15								15
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	2,016				1,990				2,016	1,990	1,897	1,712	1,590	1,385	1,183	888	420	32
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2008 | U.S. Property and Special Risks
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	3,575				3,576				3,575	3,576	3,581	3,585	3,609	3,659	3,700	3,747	3,789	3,531
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(1)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 20								$ 20
Cumulative Number of Reported Claims | item	56,526								56,526
Incurred Impact of Adverse Development Reinsurance Agreement	$ (14)								$ (14)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	3,561								3,561
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	6								6
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	3,540				3,530				3,540	3,530	3,515	3,498	3,487	3,457	3,342	3,150	2,679	1,323
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2008 | U.S. Personal Insurance
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,668				1,664				1,668	1,664	1,666	1,663	1,654	1,654	1,654	1,640	1,638	1,630
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									4
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 1								$ 1
Cumulative Number of Reported Claims | item	292,830								292,830
Incurred Impact of Adverse Development Reinsurance Agreement	$ (1)								$ (1)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,667								1,667
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	0								0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,665				1,663				1,665	1,663	1,660	1,656	1,644	1,634	1,609	1,569	1,493	1,151
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2008 | Europe Casualty and Financial Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,604				1,604				1,604	1,604	1,605	1,649	1,599	1,595	1,580	1,632	1,615	1,511
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									0
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 24								$ 24
Cumulative Number of Reported Claims | item	236,384								236,384
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 1,471				1,455				$ 1,471	1,455	1,375	1,323	1,245	1,118	961	726	477	130
2008 | Europe Property and Special Risks
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	613				614				613	614	618	620	626	632	643	644	636	633
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(1)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 0								$ 0
Cumulative Number of Reported Claims | item	41,602								41,602
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 599				598				$ 599	598	596	596	590	577	546	511	399	148
2008 | Europe and Japan Personal Insurance
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,914				2,912				2,914	2,912	2,916	2,913	2,919	2,915	2,908	2,904	2,911	2,869
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									2
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 3								$ 3
Cumulative Number of Reported Claims | item	1,577,002								1,577,002
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 2,899				2,896				$ 2,899	2,896	2,887	2,880	2,865	2,829	2,773	2,655	2,421	1,602
2008 | U.S. Run-Off Long Tail Insurance Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	985				983				985	983	976	978	926	909	868	884	1,035	945
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									2
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 65								$ 65
Cumulative Number of Reported Claims | item	40,075								40,075
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 866				846				$ 866	846	832	787	726	657	572	497	370	$ 133
2009 | U.S. Workers Compensation
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	3,714				3,708				3,714	3,708	3,606	3,616	3,639	3,666	3,608	3,633	3,466
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									6
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 495								$ 495
Cumulative Number of Reported Claims | item	147,357								147,357
Incurred Impact of Adverse Development Reinsurance Agreement	$ (416)								$ (416)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	3,298								3,298
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	79								79
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	2,968				2,887				2,968	2,887	2,780	2,621	2,390	2,120	1,756	1,328	630
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2009 | U.S. Excess Casualty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,522				1,518				1,522	1,518	1,407	1,321	1,457	1,638	1,797	1,897	1,831
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									4
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 210								$ 210
Cumulative Number of Reported Claims | item	3,789								3,789
Incurred Impact of Adverse Development Reinsurance Agreement	$ (169)								$ (169)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,353								1,353
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	41								41
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,212				1,174				1,212	1,174	965	788	624	449	249	69	8
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2009 | U.S. Other Casualty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,855				2,863				2,855	2,863	2,880	2,818	2,697	2,582	2,586	2,517	2,416
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(8)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 144								$ 144
Cumulative Number of Reported Claims | item	90,101								90,101
Incurred Impact of Adverse Development Reinsurance Agreement	$ (143)								$ (143)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	2,712								2,712
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	1								1
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	2,664				2,607				2,664	2,607	2,386	2,241	2,002	1,650	1,253	842	393
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2009 | U.S. Financial Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,310				2,273				2,310	2,273	2,183	2,189	2,097	1,904	1,845	1,780	1,693
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									37
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 60								$ 60
Cumulative Number of Reported Claims | item	22,613								22,613
Incurred Impact of Adverse Development Reinsurance Agreement	$ (26)								$ (26)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	2,284								2,284
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	34								34
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	2,092				2,056				2,092	2,056	1,964	1,838	1,614	1,273	887	499	129
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2009 | U.S. Property and Special Risks
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,663				1,664				1,663	1,664	1,656	1,665	1,662	1,700	1,689	1,704	1,919
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(1)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 18								$ 18
Cumulative Number of Reported Claims | item	42,897								42,897
Incurred Impact of Adverse Development Reinsurance Agreement	$ (13)								$ (13)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,650								1,650
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	5								5
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,633				1,618				1,633	1,618	1,597	1,580	1,528	1,443	1,288	1,044	495
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2009 | U.S. Personal Insurance
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,671				1,667				1,671	1,667	1,668	1,664	1,664	1,663	1,649	1,697	1,763
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									4
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 4								$ 4
Cumulative Number of Reported Claims | item	375,959								375,959
Incurred Impact of Adverse Development Reinsurance Agreement	$ 0								$ 0
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,671								1,671
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	4								4
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,664				1,663				1,664	1,663	1,658	1,650	1,639	1,618	1,567	1,563	1,129
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2009 | Europe Casualty and Financial Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,030				1,996				2,030	1,996	1,912	1,906	1,885	1,856	1,858	1,844	1,746
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									34
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 103								$ 103
Cumulative Number of Reported Claims | item	236,270								236,270
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 1,681				1,581				$ 1,681	1,581	1,442	1,274	1,139	970	708	418	139
2009 | Europe Property and Special Risks
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	655				655				655	655	655	680	666	674	675	666	738
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									0
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 3								$ 3
Cumulative Number of Reported Claims | item	39,109								39,109
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 635				634				$ 635	634	632	620	613	585	532	429	183
2009 | Europe and Japan Personal Insurance
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,902				2,902				2,902	2,902	2,900	2,907	2,909	2,920	2,901	2,900	2,913
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									0
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 5								$ 5
Cumulative Number of Reported Claims | item	1,605,992								1,605,992
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 2,886				2,879				$ 2,886	2,879	2,867	2,850	2,821	2,765	2,656	2,412	1,627
2009 | U.S. Run-Off Long Tail Insurance Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	576				580				576	580	599	602	635	579	544	532	553
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(4)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 75								$ 75
Cumulative Number of Reported Claims | item	16,237								16,237
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 461				447				$ 461	447	429	409	368	286	231	134	$ 42
2010 | U.S. Workers Compensation
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	3,267				3,286				3,267	3,286	3,214	3,211	3,148	3,125	3,049	2,706
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(19)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 451								$ 451
Cumulative Number of Reported Claims | item	133,191								133,191
Incurred Impact of Adverse Development Reinsurance Agreement	$ (449)								$ (449)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	2,818								2,818
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	2								2
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	2,532				2,426				2,532	2,426	2,288	2,126	1,855	1,537	1,093	550
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2010 | U.S. Excess Casualty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,706				1,719				1,706	1,719	1,723	1,640	1,771	2,076	2,076	1,863
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(13)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 359								$ 359
Cumulative Number of Reported Claims | item	3,588								3,588
Incurred Impact of Adverse Development Reinsurance Agreement	$ (260)								$ (260)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,446								1,446
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	99								99
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,217				1,052				1,217	1,052	946	795	654	475	197	10
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2010 | U.S. Other Casualty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,494				2,503				2,494	2,503	2,384	2,341	2,192	2,243	2,109	2,132
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(9)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 325								$ 325
Cumulative Number of Reported Claims | item	96,061								96,061
Incurred Impact of Adverse Development Reinsurance Agreement	$ (133)								$ (133)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	2,361								2,361
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	192								192
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	2,087				1,972				2,087	1,972	1,824	1,640	1,358	985	661	295
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2010 | U.S. Financial Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,541				1,514				1,541	1,514	1,472	1,370	1,366	1,406	1,509	1,552
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									27
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 70								$ 70
Cumulative Number of Reported Claims | item	20,159								20,159
Incurred Impact of Adverse Development Reinsurance Agreement	$ (31)								$ (31)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,510								1,510
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	39								39
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,361				1,280				1,361	1,280	1,180	1,017	800	566	285	31
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2010 | U.S. Property and Special Risks
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,058				2,043				2,058	2,043	2,038	2,061	2,049	2,009	2,042	2,275
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									15
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 21								$ 21
Cumulative Number of Reported Claims | item	42,276								42,276
Incurred Impact of Adverse Development Reinsurance Agreement	$ (18)								$ (18)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	2,040								2,040
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	3								3
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	2,001				1,978				2,001	1,978	1,940	1,880	1,799	1,657	1,391	654
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2010 | U.S. Personal Insurance
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,817				1,817				1,817	1,817	1,819	1,820	1,819	1,819	1,809	1,843
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									0
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 2								$ 2
Cumulative Number of Reported Claims | item	422,527								422,527
Incurred Impact of Adverse Development Reinsurance Agreement	$ (1)								$ (1)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,816								1,816
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	1								1
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,810				1,808				1,810	1,808	1,803	1,794	1,772	1,736	1,669	1,205
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2010 | Europe Casualty and Financial Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,445				1,377				1,445	1,377	1,420	1,380	1,457	1,432	1,436	1,484
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									68
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 77								$ 77
Cumulative Number of Reported Claims | item	274,310								274,310
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 1,162				1,109				$ 1,162	1,109	1,042	947	808	635	420	147
2010 | Europe Property and Special Risks
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	707				706				707	706	703	712	703	719	747	788
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									1
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 0								$ 0
Cumulative Number of Reported Claims | item	40,389								40,389
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 693				690				$ 693	690	686	672	634	584	489	187
2010 | Europe and Japan Personal Insurance
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	3,030				3,027				3,030	3,027	2,999	3,004	3,003	3,015	3,007	2,969
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									3
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 8								$ 8
Cumulative Number of Reported Claims | item	1,819,631								1,819,631
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 2,975				2,963				$ 2,975	2,963	2,944	2,909	2,852	2,741	2,497	1,703
2010 | U.S. Run-Off Long Tail Insurance Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	565				611				565	611	582	585	557	534	528	640
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(46)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 68								$ 68
Cumulative Number of Reported Claims | item	8,490								8,490
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 464				455				$ 464	455	435	404	321	243	149	$ 57
2011 | U.S. Workers Compensation
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	3,156				3,152				3,156	3,152	3,113	3,158	3,091	2,953	2,901
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									4
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 481								$ 481
Cumulative Number of Reported Claims | item	124,657								124,657
Incurred Impact of Adverse Development Reinsurance Agreement	$ (479)								$ (479)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	2,677								2,677
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	2								2
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	2,388				2,285				2,388	2,285	2,129	1,884	1,561	1,129	519
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2011 | U.S. Excess Casualty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,623				1,606				1,623	1,606	1,521	1,416	1,581	1,807	1,766
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									17
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 350								$ 350
Cumulative Number of Reported Claims | item	3,520								3,520
Incurred Impact of Adverse Development Reinsurance Agreement	$ (256)								$ (256)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,367								1,367
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	94								94
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,069				921				1,069	921	716	386	225	63	5
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2011 | U.S. Other Casualty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,596				2,639				2,596	2,639	2,601	2,458	2,321	2,222	2,052
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(43)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 256								$ 256
Cumulative Number of Reported Claims | item	75,189								75,189
Incurred Impact of Adverse Development Reinsurance Agreement	$ (187)								$ (187)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	2,409								2,409
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	69								69
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	2,220				2,048				2,220	2,048	1,822	1,488	1,109	726	235
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2011 | U.S. Financial Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,997				1,965				1,997	1,965	1,935	1,902	1,902	1,734	1,816
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									32
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 50								$ 50
Cumulative Number of Reported Claims | item	20,048								20,048
Incurred Impact of Adverse Development Reinsurance Agreement	$ (50)								$ (50)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,947								1,947
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	0								0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,862				1,732				1,862	1,732	1,528	1,210	886	494	165
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2011 | U.S. Property and Special Risks
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,919				2,910				2,919	2,910	2,867	2,878	2,872	2,917	3,045
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									9
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 43								$ 43
Cumulative Number of Reported Claims | item	43,849								43,849
Incurred Impact of Adverse Development Reinsurance Agreement	$ (19)								$ (19)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	2,900								2,900
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	24								24
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	2,840				2,812				2,840	2,812	2,734	2,593	2,417	1,988	880
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2011 | U.S. Personal Insurance
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,881				1,886				1,881	1,886	1,890	1,891	1,896	1,908	1,886
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(5)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 1								$ 1
Cumulative Number of Reported Claims | item	412,670								412,670
Incurred Impact of Adverse Development Reinsurance Agreement	$ (1)								$ (1)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,880								1,880
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	0								0
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,873				1,869				1,873	1,869	1,860	1,840	1,814	1,752	1,204
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2011 | Europe Casualty and Financial Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,597				1,554				1,597	1,554	1,552	1,465	1,426	1,352	1,414
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									43
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 83								$ 83
Cumulative Number of Reported Claims | item	264,629								264,629
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 1,224				1,108				$ 1,224	1,108	963	811	564	376	140
2011 | Europe Property and Special Risks
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	628				628				628	628	631	642	648	687	763
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									0
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 0								$ 0
Cumulative Number of Reported Claims | item	39,925								39,925
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 604				599				$ 604	599	591	581	543	444	181
2011 | Europe and Japan Personal Insurance
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	3,287				3,288				3,287	3,288	3,284	3,295	3,293	3,324	3,274
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(1)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 10								$ 10
Cumulative Number of Reported Claims | item	1,777,001								1,777,001
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 3,244				3,227				$ 3,244	3,227	3,198	3,134	3,022	2,787	1,987
2011 | U.S. Run-Off Long Tail Insurance Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	700				685				700	685	676	641	576	542	534
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									15
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 97								$ 97
Cumulative Number of Reported Claims | item	7,798								7,798
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 549				532				$ 549	532	449	385	259	140	$ 21
2012 | U.S. Workers Compensation
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,308				2,334				2,308	2,334	2,260	2,286	2,194	2,382
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(26)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 503								$ 503
Cumulative Number of Reported Claims | item	70,625								70,625
Incurred Impact of Adverse Development Reinsurance Agreement	$ (494)								$ (494)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,814								1,814
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	9								9
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,563				1,440				1,563	1,440	1,272	1,089	804	415
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2012 | U.S. Excess Casualty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,481				1,530				1,481	1,530	1,477	1,226	1,382	1,588
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(49)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 371								$ 371
Cumulative Number of Reported Claims | item	3,398								3,398
Incurred Impact of Adverse Development Reinsurance Agreement	$ (323)								$ (323)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,158								1,158
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	48								48
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	887				649				887	649	495	288	106	3
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2012 | U.S. Other Casualty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,430				2,371				2,430	2,371	2,229	2,218	2,162	2,012
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									59
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 382								$ 382
Cumulative Number of Reported Claims | item	41,924								41,924
Incurred Impact of Adverse Development Reinsurance Agreement	$ (210)								$ (210)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	2,220								2,220
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	172								172
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,882				1,690				1,882	1,690	1,395	1,048	743	413
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2012 | U.S. Financial Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,987				1,986				1,987	1,986	1,892	1,777	1,739	1,572
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									1
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 146								$ 146
Cumulative Number of Reported Claims | item	20,090								20,090
Incurred Impact of Adverse Development Reinsurance Agreement	$ (83)								$ (83)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,904								1,904
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	63								63
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,625				1,497				1,625	1,497	1,252	815	406	76
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2012 | U.S. Property and Special Risks
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	3,691				3,697				3,691	3,697	3,576	3,585	3,617	3,470
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(6)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 62								$ 62
Cumulative Number of Reported Claims | item	42,278								42,278
Incurred Impact of Adverse Development Reinsurance Agreement	$ (25)								$ (25)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	3,666								3,666
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	37								37
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	3,565				3,456				3,565	3,456	3,273	2,978	2,410	734
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2012 | U.S. Personal Insurance
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,094				2,077				2,094	2,077	2,083	2,109	2,128	2,208
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									17
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 4								$ 4
Cumulative Number of Reported Claims | item	403,542								403,542
Incurred Impact of Adverse Development Reinsurance Agreement	$ (3)								$ (3)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	2,091								2,091
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	1								1
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	2,079				2,065				2,079	2,065	2,035	1,996	1,936	1,238
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2012 | Europe Casualty and Financial Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,232				1,263				1,232	1,263	1,222	1,150	1,193	1,224
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(31)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 103								$ 103
Cumulative Number of Reported Claims | item	217,887								217,887
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 897				809				$ 897	809	677	484	334	121
2012 | Europe Property and Special Risks
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	627				615				627	615	630	648	682	728
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									12
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ (2)								$ (2)
Cumulative Number of Reported Claims | item	34,457								34,457
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 580				572				$ 580	572	549	511	410	154
2012 | Europe and Japan Personal Insurance
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,846				2,845				2,846	2,845	2,836	2,851	2,867	2,898
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									1
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 16								$ 16
Cumulative Number of Reported Claims | item	1,729,298								1,729,298
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 2,785				2,754				$ 2,785	2,754	2,698	2,591	2,363	1,614
2012 | U.S. Run-Off Long Tail Insurance Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	752				751				752	751	786	741	678	629
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									1
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 104								$ 104
Cumulative Number of Reported Claims | item	4,053								4,053
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 498				481				$ 498	481	414	286	194	$ 86
2013 | U.S. Workers Compensation
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,032				2,060				2,032	2,060	1,950	1,880	1,932
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(28)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 548								$ 548
Cumulative Number of Reported Claims | item	46,483								46,483
Incurred Impact of Adverse Development Reinsurance Agreement	$ (538)								$ (538)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,494								1,494
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	10								10
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,214				1,067				1,214	1,067	879	619	282
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2013 | U.S. Excess Casualty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,178				1,258				1,178	1,258	1,113	973	1,073
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(80)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 441								$ 441
Cumulative Number of Reported Claims | item	2,722								2,722
Incurred Impact of Adverse Development Reinsurance Agreement	$ (309)								$ (309)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	869								869
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	132								132
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	546				382				546	382	204	104	15
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2013 | U.S. Other Casualty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,183				2,152				2,183	2,152	1,918	1,739	1,662
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									31
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 450								$ 450
Cumulative Number of Reported Claims | item	36,699								36,699
Incurred Impact of Adverse Development Reinsurance Agreement	$ (225)								$ (225)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,958								1,958
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	225								225
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,483				1,243				1,483	1,243	956	592	169
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2013 | U.S. Financial Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,541				1,597				1,541	1,597	1,643	1,691	1,767
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(56)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 248								$ 248
Cumulative Number of Reported Claims | item	18,996								18,996
Incurred Impact of Adverse Development Reinsurance Agreement	$ (126)								$ (126)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,415								1,415
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	122								122
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,142				945				1,142	945	686	333	43
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2013 | U.S. Property and Special Risks
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,949				1,926				1,949	1,926	1,859	1,972	1,975
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									23
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 74								$ 74
Cumulative Number of Reported Claims | item	41,937								41,937
Incurred Impact of Adverse Development Reinsurance Agreement	$ (38)								$ (38)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,911								1,911
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	36								36
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,732				1,620				1,732	1,620	1,469	1,275	586
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2013 | U.S. Personal Insurance
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,780				1,782				1,780	1,782	1,803	1,816	1,887
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(2)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 7								$ 7
Cumulative Number of Reported Claims | item	334,474								334,474
Incurred Impact of Adverse Development Reinsurance Agreement	$ (6)								$ (6)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,774								1,774
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	1								1
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,759				1,744				1,759	1,744	1,705	1,634	1,109
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2013 | Europe Casualty and Financial Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,305				1,258				1,305	1,258	1,257	1,277	1,221
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									47
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 194								$ 194
Cumulative Number of Reported Claims | item	185,435								185,435
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 877				736				$ 877	736	543	375	105
2013 | Europe Property and Special Risks
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	842				840				842	840	842	915	914
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									2
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ (1)								$ (1)
Cumulative Number of Reported Claims | item	32,405								32,405
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 786				751				$ 786	751	700	535	193
2013 | Europe and Japan Personal Insurance
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,702				2,706				2,702	2,706	2,705	2,736	2,747
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(4)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 25								$ 25
Cumulative Number of Reported Claims | item	1,734,759								1,734,759
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 2,625				2,569				$ 2,625	2,569	2,462	2,246	1,503
2013 | U.S. Run-Off Long Tail Insurance Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	528				570				528	570	589	533	482
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(42)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 84								$ 84
Cumulative Number of Reported Claims | item	2,510								2,510
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 368				321				$ 368	321	261	154	$ 87
2014 | U.S. Workers Compensation
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,862				1,866				1,862	1,866	1,764	1,729
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(4)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 664								$ 664
Cumulative Number of Reported Claims | item	39,408								39,408
Incurred Impact of Adverse Development Reinsurance Agreement	$ (552)								$ (552)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,310								1,310
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	112								112
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	930				786				930	786	558	231
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2014 | U.S. Excess Casualty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,135				1,157				1,135	1,157	968	849
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(22)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 583								$ 583
Cumulative Number of Reported Claims | item	2,088								2,088
Incurred Impact of Adverse Development Reinsurance Agreement	$ (355)								$ (355)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	780								780
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	228								228
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	397				202				397	202	68	3
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2014 | U.S. Other Casualty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,017				1,973				2,017	1,973	1,729	1,756
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									44
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 603								$ 603
Cumulative Number of Reported Claims | item	34,745								34,745
Incurred Impact of Adverse Development Reinsurance Agreement	$ (331)								$ (331)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,686								1,686
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	272								272
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,157				871				1,157	871	621	210
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2014 | U.S. Financial Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,898				1,849				1,898	1,849	1,736	1,767
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									49
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 417								$ 417
Cumulative Number of Reported Claims | item	17,249								17,249
Incurred Impact of Adverse Development Reinsurance Agreement	$ (198)								$ (198)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,700								1,700
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	219								219
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,159				853				1,159	853	371	66
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2014 | U.S. Property and Special Risks
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,213				2,220				2,213	2,220	2,143	2,355
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(7)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 140								$ 140
Cumulative Number of Reported Claims | item	50,160								50,160
Incurred Impact of Adverse Development Reinsurance Agreement	$ (61)								$ (61)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	2,152								2,152
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	79								79
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,869				1,713				1,869	1,713	1,452	745
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2014 | U.S. Personal Insurance
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,572				1,572				1,572	1,572	1,562	1,552
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									0
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 19								$ 19
Cumulative Number of Reported Claims | item	273,481								273,481
Incurred Impact of Adverse Development Reinsurance Agreement	$ (8)								$ (8)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,564								1,564
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	11								11
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,507				1,463				1,507	1,463	1,380	959
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2014 | Europe Casualty and Financial Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,303				1,302				1,303	1,302	1,267	1,280
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									1
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 340								$ 340
Cumulative Number of Reported Claims | item	175,630								175,630
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 628				494				$ 628	494	299	86
2014 | Europe Property and Special Risks
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,050				1,052				1,050	1,052	1,046	994
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(2)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 1								$ 1
Cumulative Number of Reported Claims | item	38,719								38,719
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 939				885				$ 939	885	669	220
2014 | Europe and Japan Personal Insurance
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,690				2,698				2,690	2,698	2,716	2,717
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(8)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 45								$ 45
Cumulative Number of Reported Claims | item	1,789,718								1,789,718
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 2,558				2,447				$ 2,558	2,447	2,225	1,476
2014 | U.S. Run-Off Long Tail Insurance Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	459				453				459	453	475	379
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									6
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 164								$ 164
Cumulative Number of Reported Claims | item	2,307								2,307
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 233				185				$ 233	185	96	$ 21
2015 | U.S. Workers Compensation
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,866				1,864				1,866	1,864	1,708
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									2
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 849								$ 849
Cumulative Number of Reported Claims | item	35,059								35,059
Incurred Impact of Adverse Development Reinsurance Agreement	$ (587)								$ (587)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,279								1,279
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	262								262
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	725				524				725	524	234
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2015 | U.S. Excess Casualty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,320				1,334				1,320	1,334	892
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(14)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 602								$ 602
Cumulative Number of Reported Claims | item	1,770								1,770
Incurred Impact of Adverse Development Reinsurance Agreement	$ (425)								$ (425)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	895								895
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	177								177
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	361				192				361	192	9
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2015 | U.S. Other Casualty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,847				1,778				1,847	1,778	1,340
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									69
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 752								$ 752
Cumulative Number of Reported Claims | item	31,409								31,409
Incurred Impact of Adverse Development Reinsurance Agreement	$ (456)								$ (456)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,391								1,391
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	296								296
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	783				321				783	321	111
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2015 | U.S. Financial Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,719				1,744				1,719	1,744	1,705
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(25)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 665								$ 665
Cumulative Number of Reported Claims | item	15,698								15,698
Incurred Impact of Adverse Development Reinsurance Agreement	$ (313)								$ (313)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,406								1,406
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	352								352
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	792				393				792	393	66
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2015 | U.S. Property and Special Risks
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,299				2,312				2,299	2,312	2,398
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(13)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 203								$ 203
Cumulative Number of Reported Claims | item	50,624								50,624
Incurred Impact of Adverse Development Reinsurance Agreement	$ (98)								$ (98)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	2,201								2,201
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	105								105
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,766				1,501				1,766	1,501	820
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2015 | U.S. Personal Insurance
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,494				1,498				1,494	1,498	1,511
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(4)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 23								$ 23
Cumulative Number of Reported Claims | item	258,241								258,241
Incurred Impact of Adverse Development Reinsurance Agreement	$ (19)								$ (19)
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,475								1,475
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	4								4
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,411				1,320				1,411	1,320	931
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2015 | Europe Casualty and Financial Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,538				1,515				1,538	1,515	1,337
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									23
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 588								$ 588
Cumulative Number of Reported Claims | item	188,348								188,348
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 486				286				$ 486	286	80
2015 | Europe Property and Special Risks
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,248				1,219				1,248	1,219	1,226
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									29
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 12								$ 12
Cumulative Number of Reported Claims | item	41,799								41,799
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 1,005				778				$ 1,005	778	290
2015 | Europe and Japan Personal Insurance
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,746				2,756				2,746	2,756	2,795
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(10)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 92								$ 92
Cumulative Number of Reported Claims | item	1,762,514								1,762,514
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 2,493				2,270				$ 2,493	2,270	1,501
2015 | U.S. Run-Off Long Tail Insurance Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	550				523				550	523	439
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									27
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 174								$ 174
Cumulative Number of Reported Claims | item	2,285								2,285
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 238				132				$ 238	132	$ 35
2016 | U.S. Workers Compensation
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,346				1,299				1,346	1,299
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									47
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 773								$ 773
Cumulative Number of Reported Claims | item	28,880								28,880
Incurred Impact of Adverse Development Reinsurance Agreement	$ 0								$ 0
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,346								1,346
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	773								773
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	378				147				378	147
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2016 | U.S. Excess Casualty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,029				790				1,029	790
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									239
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 870								$ 870
Cumulative Number of Reported Claims | item	1,061								1,061
Incurred Impact of Adverse Development Reinsurance Agreement	$ 0								$ 0
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,029								1,029
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	870								870
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	66				14				66	14
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2016 | U.S. Other Casualty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,352				1,348				1,352	1,348
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									4
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 853								$ 853
Cumulative Number of Reported Claims | item	23,868								23,868
Incurred Impact of Adverse Development Reinsurance Agreement	$ 0								$ 0
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,352								1,352
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	853								853
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	299				77				299	77
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2016 | U.S. Financial Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,841				1,593				1,841	1,593
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									248
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 1,036								$ 1,036
Cumulative Number of Reported Claims | item	15,386								15,386
Incurred Impact of Adverse Development Reinsurance Agreement	$ 0								$ 0
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,841								1,841
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	1,036								1,036
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	500				76				500	76
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2016 | U.S. Property and Special Risks
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,580				2,516				2,580	2,516
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									64
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 402								$ 402
Cumulative Number of Reported Claims | item	45,583								45,583
Incurred Impact of Adverse Development Reinsurance Agreement	$ 0								$ 0
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	2,580								2,580
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	402								402
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,689				799				1,689	799
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2016 | U.S. Personal Insurance
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,533				1,536				1,533	1,536
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(3)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 73								$ 73
Cumulative Number of Reported Claims | item	240,892								240,892
Incurred Impact of Adverse Development Reinsurance Agreement	$ 0								$ 0
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,533								1,533
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	73								73
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1,344				857				1,344	857
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2016 | Europe Casualty and Financial Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,716				1,563				1,716	1,563
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									153
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 724								$ 724
Cumulative Number of Reported Claims | item	221,122								221,122
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 426				140				$ 426	140
2016 | Europe Property and Special Risks
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,239				1,118				1,239	1,118
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									121
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 24								$ 24
Cumulative Number of Reported Claims | item	40,629								40,629
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 894				300				$ 894	300
2016 | Europe and Japan Personal Insurance
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,692				2,734				2,692	2,734
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(42)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 194								$ 194
Cumulative Number of Reported Claims | item	1,762,768								1,762,768
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 2,231				1,500				$ 2,231	1,500
2016 | U.S. Run-Off Long Tail Insurance Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	285				294				285	294
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement									(9)
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 98								$ 98
Cumulative Number of Reported Claims | item	1,591								1,591
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 140				$ 53				$ 140	$ 53
2017 | U.S. Workers Compensation
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	789								789
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 577								$ 577
Cumulative Number of Reported Claims | item	22,523								22,523
Incurred Impact of Adverse Development Reinsurance Agreement	$ 0								$ 0
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	789								789
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	577								577
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	93								93
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2017 | U.S. Excess Casualty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	758								758
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 725								$ 725
Cumulative Number of Reported Claims | item	376								376
Incurred Impact of Adverse Development Reinsurance Agreement	$ 0								$ 0
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	758								758
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	725								725
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	1								1
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2017 | U.S. Other Casualty
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	616								616
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 487								$ 487
Cumulative Number of Reported Claims | item	15,172								15,172
Incurred Impact of Adverse Development Reinsurance Agreement	$ 0								$ 0
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	616								616
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	487								487
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	51								51
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2017 | U.S. Financial Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,560								1,560
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 1,369								$ 1,369
Cumulative Number of Reported Claims | item	13,428								13,428
Incurred Impact of Adverse Development Reinsurance Agreement	$ 0								$ 0
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	1,560								1,560
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	1,369								1,369
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	66								66
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2017 | U.S. Property and Special Risks
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	4,085								4,085
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 1,331								$ 1,331
Cumulative Number of Reported Claims | item	29,709								29,709
Incurred Impact of Adverse Development Reinsurance Agreement	$ 0								$ 0
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	4,085								4,085
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	1,331								1,331
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	954								954
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2017 | U.S. Personal Insurance
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,028								2,028
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 571								$ 571
Cumulative Number of Reported Claims | item	185,198								185,198
Incurred Impact of Adverse Development Reinsurance Agreement	$ 0								$ 0
2017 (Net of Impact of Adverse Development Reinsurance Agreement)	2,028								2,028
Total of IBNR Liabilities Net of Impact Adverse Development Reinsurance Agreement	571								571
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	941								941
Paid Impact of Adverse Development Reinsurance Agreement	0								0
2017 | Europe Casualty and Financial Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,587								1,587
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 1,214								$ 1,214
Cumulative Number of Reported Claims | item	204,712								204,712
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 113								$ 113
2017 | Europe Property and Special Risks
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	1,377								1,377
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 390								$ 390
Cumulative Number of Reported Claims | item	29,313								29,313
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 236								$ 236
2017 | Europe and Japan Personal Insurance
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	2,659								2,659
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 549								$ 549
Cumulative Number of Reported Claims | item	1,502,118								1,502,118
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 1,465								$ 1,465
2017 | U.S. Run-Off Long Tail Insurance Lines
Claims Development [Line Items]
Incurred Losses and Allocated Loss Adjustment Expenses, Undiscounted and Net of Reinsurance	197								197
Total of IBNR Liabilities Plus Expected Development on Reported Losses	$ 163								$ 163
Cumulative Number of Reported Claims | item	607								607
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	$ 13								$ 13
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement | U.S. Workers Compensation
Claims Development [Line Items]
Total	(29)								(29)
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0								0
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	4								4
Unallocated Loss Adjustment Expense Prior Year Development	(6)								(6)
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	(31)								(31)
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement | U.S. Excess Casualty
Claims Development [Line Items]
Total	105								105
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0								0
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	141								141
Unallocated Loss Adjustment Expense Prior Year Development	8								8
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	254								254
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement | U.S. Other Casualty
Claims Development [Line Items]
Total	129								129
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0								0
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	10								10
Unallocated Loss Adjustment Expense Prior Year Development	77								77
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	216								216
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement | U.S. Financial Lines
Claims Development [Line Items]
Total	323								323
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0								0
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	(44)								(44)
Unallocated Loss Adjustment Expense Prior Year Development	66								66
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	345								345
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement | U.S. Property and Special Risks
Claims Development [Line Items]
Total	83								83
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0								0
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	12								12
Unallocated Loss Adjustment Expense Prior Year Development	20								20
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	115								115
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement | U.S. Personal Insurance
Claims Development [Line Items]
Total	11								11
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0								0
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	5								5
Unallocated Loss Adjustment Expense Prior Year Development	0								0
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	16								16
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement | Europe Casualty and Financial Lines
Claims Development [Line Items]
Total	338								338
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0								0
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	169								169
Unallocated Loss Adjustment Expense Prior Year Development	0								0
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	507								507
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement | Europe Property and Special Risks
Claims Development [Line Items]
Total	162								162
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0								0
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	(5)								(5)
Unallocated Loss Adjustment Expense Prior Year Development	0								0
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	157								157
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement | Europe and Japan Personal Insurance
Claims Development [Line Items]
Total	(59)								(59)
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0								0
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	1								1
Unallocated Loss Adjustment Expense Prior Year Development	0								0
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	(58)								(58)
2017 Prior Year Development Excluding the Impact of Adverse Development Reinsurance Agreement | U.S. Run-Off Long Tail Insurance Lines
Claims Development [Line Items]
Total	(50)								(50)
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0								0
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	(46)								(46)
Unallocated Loss Adjustment Expense Prior Year Development	66								66
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	(30)								(30)
Incurred Impact of Adverse Development Reinsurance Agreement | U.S. Workers Compensation
Claims Development [Line Items]
Total	(3,931)								(3,931)
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0								0
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	(1,616)								(1,616)
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	(5,547)								(5,547)
Incurred Impact of Adverse Development Reinsurance Agreement | U.S. Excess Casualty
Claims Development [Line Items]
Total	(2,273)								(2,273)
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0								0
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	(864)								(864)
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	(3,137)								(3,137)
Incurred Impact of Adverse Development Reinsurance Agreement | U.S. Other Casualty
Claims Development [Line Items]
Total	(1,789)								(1,789)
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0								0
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	(512)								(512)
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	(2,301)								(2,301)
Incurred Impact of Adverse Development Reinsurance Agreement | U.S. Financial Lines
Claims Development [Line Items]
Total	(848)								(848)
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0								0
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	(21)								(21)
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	(869)								(869)
Incurred Impact of Adverse Development Reinsurance Agreement | U.S. Property and Special Risks
Claims Development [Line Items]
Total	(286)								(286)
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0								0
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	(65)								(65)
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	(351)								(351)
Incurred Impact of Adverse Development Reinsurance Agreement | U.S. Personal Insurance
Claims Development [Line Items]
Total	(39)								(39)
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0								0
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	(1)								(1)
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	(40)								(40)
2017 (Net of Impact of Adverse Development Reinsurance Agreement) | U.S. Workers Compensation
Claims Development [Line Items]
Total	20,945								20,945
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	(16,580)								(16,580)
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	2,251								2,251
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	6,616								6,616
2017 (Net of Impact of Adverse Development Reinsurance Agreement) | U.S. Excess Casualty
Claims Development [Line Items]
Total	11,137								11,137
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	(7,120)								(7,120)
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	785								785
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	4,802								4,802
2017 (Net of Impact of Adverse Development Reinsurance Agreement) | U.S. Other Casualty
Claims Development [Line Items]
Total	19,776								19,776
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	(15,521)								(15,521)
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	894								894
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	5,149								5,149
2017 (Net of Impact of Adverse Development Reinsurance Agreement) | U.S. Financial Lines
Claims Development [Line Items]
Total	17,652								17,652
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	(12,615)								(12,615)
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	67								67
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	5,104								5,104
2017 (Net of Impact of Adverse Development Reinsurance Agreement) | U.S. Property and Special Risks
Claims Development [Line Items]
Total	26,746								26,746
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	(21,589)								(21,589)
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	253								253
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	5,410								5,410
2017 (Net of Impact of Adverse Development Reinsurance Agreement) | U.S. Personal Insurance
Claims Development [Line Items]
Total	17,499								17,499
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	(16,053)								(16,053)
Liabilities for losses and loss adjustment expenses and prior year development before 2008, net of reinsurance	(66)								(66)
Liabilities for losses and loss adjustment expenses and prior year loss development, net of reinsurance	1,380								1,380
Paid Impact of Adverse Development Reinsurance Agreement | U.S. Workers Compensation
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0								0
Paid Impact of Adverse Development Reinsurance Agreement | U.S. Excess Casualty
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0								0
Paid Impact of Adverse Development Reinsurance Agreement | U.S. Other Casualty
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0								0
Paid Impact of Adverse Development Reinsurance Agreement | U.S. Financial Lines
Claims Development [Line Items]
Cumulative Paid Losses and Allocated Loss Adjustment Expenses, Net of Reinsurance	0								0
Paid Impact of Adverse Development Reinsurance Agreement | U.S. Property and Special Risks
Claims Development [Line Items]
Paid Impact of Adverse Development Reinsurance Agreement	0								0
Paid Impact of Adverse Development Reinsurance Agreement | U.S. Personal Insurance
Claims Development [Line Items]
Paid Impact of Adverse Development Reinsurance Agreement	$ 0								$ 0