Consolidating Financial Statements (details) - Consolidating Statement of Income (Unaudited) - USD ($) $ in Millions		3 Months Ended		6 Months Ended
		Jun. 30, 2015	Jun. 30, 2014	Jun. 30, 2015	Jun. 30, 2014
Consolidating Statement of Income
Premiums		$ 5,931	$ 5,928	$ 11,819	$ 11,751
Net investment income		632	695	1,224	1,431
Fee income		111	112	222	219
Net realized investment gains (losses)	[1]	10	16	20	17
Other revenues		22	34	47	75
Total revenues		6,706	6,785	13,332	13,493
Claims and claim adjustment expenses		3,547	3,826	6,978	7,141
Amortization of deferred acquisition costs		963	965	1,926	1,915
General and administrative expenses		1,028	1,001	2,020	1,882
Interest expense		92	92	184	184
Total claims and expenses		5,630	5,884	11,108	11,122
Income before income taxes		1,076	901	2,224	2,371
Income tax expense (benefit)		264	218	579	636
Net income		812	683	1,645	1,735
Total other-than-temporary impairment losses		(8)	(1)	(12)	(8)
Other-than-temporary impairment losses recognized in net realized investment gains		(6)	(1)	(9)	(10)
Other-than-temporary impairment gains (losses) recognized in OCI		(2)	0	(3)	2
Reportable Legal Entities [Member] | TPC [Member]
Consolidating Statement of Income
Premiums		4,044	4,020	8,040	7,964
Net investment income		424	472	835	972
Fee income		111	111	222	218
Net realized investment gains (losses)		17	5	19	6
Other revenues		19	32	40	65
Total revenues		4,615	4,640	9,156	9,225
Claims and claim adjustment expenses		2,409	2,569	4,718	4,790
Amortization of deferred acquisition costs		651	650	1,293	1,285
General and administrative expenses		717	697	1,412	1,310
Interest expense		12	12	24	24
Total claims and expenses		3,789	3,928	7,447	7,409
Income before income taxes		826	712	1,709	1,816
Income tax expense (benefit)		198	186	449	507
Net income		628	526	1,260	1,309
Total other-than-temporary impairment losses		(7)	(1)	(8)	(3)
Other-than-temporary impairment losses recognized in net realized investment gains		(5)	(1)	(6)	(5)
Other-than-temporary impairment gains (losses) recognized in OCI		(2)		(2)	2
Reportable Legal Entities [Member] | Other Subsidiaries [Member]
Consolidating Statement of Income
Premiums		1,887	1,908	3,779	3,787
Net investment income		206	221	386	456
Fee income			1		1
Net realized investment gains (losses)		(7)	11		9
Other revenues		3	2	7	10
Total revenues		2,089	2,143	4,172	4,263
Claims and claim adjustment expenses		1,138	1,257	2,260	2,351
Amortization of deferred acquisition costs		312	315	633	630
General and administrative expenses		308	300	600	565
Total claims and expenses		1,758	1,872	3,493	3,546
Income before income taxes		331	271	679	717
Income tax expense (benefit)		86	60	179	185
Net income		245	211	500	532
Total other-than-temporary impairment losses		(1)		(4)	(5)
Other-than-temporary impairment losses recognized in net realized investment gains		(1)		(3)	(5)
Other-than-temporary impairment gains (losses) recognized in OCI				(1)
Reportable Legal Entities [Member] | Travelers [Member]
Consolidating Statement of Income
Net investment income		2	2	3	3
Net realized investment gains (losses)				1	2
Total revenues		2	2	4	5
General and administrative expenses		3	4	8	7
Interest expense		80	80	160	160
Total claims and expenses		83	84	168	167
Income before income taxes		(81)	(82)	(164)	(162)
Income tax expense (benefit)		(20)	(28)	(49)	(56)
Net income of subsidiaries		873	737	1,760	1,841
Net income		812	683	1,645	1,735
Eliminations [Member]
Consolidating Statement of Income
Net income of subsidiaries		(873)	(737)	(1,760)	(1,841)
Net income		$ (873)	$ (737)	$ (1,760)	$ (1,841)

[1] Total other-than-temporary impairment (OTTI) losses were $(8) million and $(1) million for the three months ended June 30, 2015 and 2014, respectively, and $(12) million and $(8) million for the six months ended June 30, 2015 and 2014, respectively. Of total OTTI, credit losses of $(6) million and $(1) million for the three months ended June 30, 2015 and 2014, respectively, and $(9) million and $(10) million for the six months ended June 30, 2015 and 2014, respectively, were recognized in net realized investment gains. In addition, unrealized gains (losses) from other changes in total OTTI of $(2) million and $0 million for the three months ended June 30, 2015 and 2014, respectively, and $(3) million and $2 million for the six months ended June 30, 2015 and 2014, respectively, were recognized in other comprehensive income (loss) as part of changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income.