Consolidating Financial Statements (details) - Consolidating Statement of Income (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended		9 Months Ended
	Sep. 30, 2012	Sep. 30, 2011	Sep. 30, 2012	Sep. 30, 2011
Consolidating Financial Statements, Captions
Premiums	$ 5,666	$ 5,605	$ 16,718	$ 16,479
Net investment income	722	690	2,200	2,227
Fee income	92	79	233	227
Net realized investment gains (losses)	(2)	2	12	41
Other revenues	34	31	100	99
Total revenues	6,512	6,407	19,263	19,073
Claims and claim adjustment expenses	3,359	4,136	10,509	12,659
Amortization of deferred acquisition costs	986	982	2,933	2,900
General and administrative expenses	904	860	2,681	2,650
Interest expense	93	97	285	290
Total claims and expenses	5,342	6,075	16,408	18,499
Income before income taxes	1,170	332	2,855	574
Income tax expense (benefit)	306	(1)	686	(234)
Net income	864	333	2,169	808
Other-than-temporary impairment losses, total gains (losses)	17	9	28	16
Other-than-temporary impairment losses, non-credit component of impairments recognized in accumulated other comprehensive income	(20)	(21)	(39)	(36)
Other-than-temporary impairment losses	(3)	(12)	(11)	(20)
Other net realized investment gains (losses)	1	14	23	61
TPC [Member]
Consolidating Financial Statements, Captions
Premiums	3,845	3,780	11,333	11,115
Net investment income	443	460	1,444	1,503
Fee income	92	78	232	225
Net realized investment gains (losses)	2	(13)	17	8
Other revenues	21	24	70	81
Total revenues	4,403	4,329	13,096	12,932
Claims and claim adjustment expenses	2,292	2,815	7,113	8,480
Amortization of deferred acquisition costs	660	654	1,953	1,921
General and administrative expenses	622	579	1,829	1,766
Interest expense	19	19	55	55
Total claims and expenses	3,593	4,067	10,950	12,222
Income before income taxes	810	262	2,146	710
Income tax expense (benefit)	212	8	536
Net income	598	254	1,610	710
Other-than-temporary impairment losses, total gains (losses)	15	13	15	12
Other-than-temporary impairment losses, non-credit component of impairments recognized in accumulated other comprehensive income	(17)	(19)	(23)	(24)
Other-than-temporary impairment losses	(2)	(6)	(8)	(12)
Other net realized investment gains (losses)	4	(7)	25	20
Other Subsidiaries [Member]
Consolidating Financial Statements, Captions
Premiums	1,821	1,825	5,385	5,364
Net investment income	277	228	750	717
Fee income		1	1	2
Net realized investment gains (losses)	(4)	15	(5)	38
Other revenues	13	7	30	18
Total revenues	2,107	2,076	6,161	6,139
Claims and claim adjustment expenses	1,067	1,321	3,396	4,179
Amortization of deferred acquisition costs	326	328	980	979
General and administrative expenses	284	279	850	859
Total claims and expenses	1,677	1,928	5,226	6,017
Income before income taxes	430	148	935	122
Income tax expense (benefit)	120	18	231	(51)
Net income	310	130	704	173
Other-than-temporary impairment losses, total gains (losses)	2	(4)	13	4
Other-than-temporary impairment losses, non-credit component of impairments recognized in accumulated other comprehensive income	(3)	(2)	(16)	(12)
Other-than-temporary impairment losses	(1)	(6)	(3)	(8)
Other net realized investment gains (losses)	(3)	21	(2)	46
Travelers [Member]
Consolidating Financial Statements, Captions
Net investment income	2	2	6	7
Net realized investment gains (losses)				(5)
Total revenues	2	2	6	2
General and administrative expenses	(2)	2	2	25
Interest expense	74	78	230	235
Total claims and expenses	72	80	232	260
Income before income taxes	(70)	(78)	(226)	(258)
Income tax expense (benefit)	(26)	(27)	(81)	(183)
Equity in net income of subsidiaries	908	384	2,314	883
Net income	864	333	2,169	808
Other net realized investment gains (losses)				(5)
Eliminations [Member]
Consolidating Financial Statements, Captions
Equity in net income of subsidiaries	(908)	(384)	(2,314)	(883)
Net income	$ (908)	$ (384)	$ (2,314)	$ (883)