Consolidating Financial Statements (details) - Consolidating Statement of Income (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2012	Sep. 30, 2012	Jun. 30, 2012	Mar. 31, 2012	Dec. 31, 2011	Sep. 30, 2011	Jun. 30, 2011	Mar. 31, 2011	Dec. 31, 2012		Dec. 31, 2011		Dec. 31, 2010
Consolidating financial statements
Premiums									$ 22,357		$ 22,090		$ 21,432
Net investment income									2,889		2,879		3,059
Fee income									323		296		287
Net realized investment gains (losses)									51	[1]	55	[1]	264	[1]
Other revenues									120		126		70
Total revenues	6,477	6,512	6,359	6,392	6,373	6,407	6,388	6,278	25,740		25,446		25,112
Claims and claim adjustment expenses									14,676		16,276		13,210
Amortization of deferred acquisition costs									3,910		3,876		3,802
General and administrative expenses									3,610		3,556		3,406
Interest expense									378		386		388
Total claims and expenses	6,166	5,342	5,751	5,315	5,595	6,075	7,115	5,309	22,574		24,094		20,806
Income before income taxes	311	1,170	608	1,077	778	332	(727)	969	3,166		1,352		4,306
Income tax expense (benefit)	7	306	109	271	160	(1)	(363)	130	693		(74)		1,090
Net income	304	864	499	806	618	333	(364)	839	2,473		1,426		3,216
Total other-than-temporary impairment gains									27		30		7
Other-than-temporary impairment losses recognized in net realized investment gains									(15)		(25)		(26)
Other-than-temporary impairment gains recognized in other comprehensive income									42		55		33
TPC [Member]
Consolidating financial statements
Premiums									15,158		14,903		14,445
Net investment income									1,912		1,933		2,078
Fee income									321		294		285
Net realized investment gains (losses)									29		10		57
Other revenues									87		103		111
Total revenues									17,507		17,243		16,976
Claims and claim adjustment expenses									9,908		10,906		8,786
Amortization of deferred acquisition costs									2,636		2,594		2,548
General and administrative expenses									2,445		2,377		2,306
Interest expense									73		73		74
Total claims and expenses									15,062		15,950		13,714
Income before income taxes									2,445		1,293		3,262
Income tax expense (benefit)									588		111		798
Net income									1,857		1,182		2,464
Total other-than-temporary impairment gains									18		15		10
Other-than-temporary impairment losses recognized in net realized investment gains									(9)		(15)		(12)
Other-than-temporary impairment gains recognized in other comprehensive income									27		30		22
Other Subsidiaries [Member]
Consolidating financial statements
Premiums									7,199		7,187		6,987
Net investment income									968		938		970
Fee income									2		2		2
Net realized investment gains (losses)									22		50		200
Other revenues									34		23		20
Total revenues									8,225		8,200		8,179
Claims and claim adjustment expenses									4,768		5,370		4,424
Amortization of deferred acquisition costs									1,274		1,282		1,254
General and administrative expenses									1,161		1,152		1,086
Total claims and expenses									7,203		7,804		6,764
Income before income taxes									1,022		396		1,415
Income tax expense (benefit)									224		14		382
Net income									798		382		1,033
Total other-than-temporary impairment gains									9		15		(3)
Other-than-temporary impairment losses recognized in net realized investment gains									(6)		(10)		(14)
Other-than-temporary impairment gains recognized in other comprehensive income									15		25		11
Travelers [Member]
Consolidating financial statements
Net investment income									9		8		11
Net realized investment gains (losses)											(5)		7
Other revenues									(1)				(60)
Total revenues									8		3		(42)
General and administrative expenses									4		27		14
Interest expense									305		313		315
Total claims and expenses									309		340		329
Income before income taxes									(301)		(337)		(371)
Income tax expense (benefit)									(119)		(199)		(90)
Net income of subsidiaries									2,655		1,564		3,497
Net income									2,473		1,426		3,216
Eliminations [Member]
Consolidating financial statements
Other revenues													(1)
Total revenues													(1)
Interest expense													(1)
Total claims and expenses													(1)
Net income of subsidiaries									(2,655)		(1,564)		(3,497)
Net income									$ (2,655)		$ (1,564)		$ (3,497)

[1] Total other-than-temporary impairment (OTTI) gains were $27 million, $30 million and $7 million for the years ended December 31, 2012, 2011 and 2010, respectively. Of total OTTI, credit losses of $(15) million, $(25) million and $(26) million for the years ended December 31, 2012, 2011 and 2010, respectively, were recognized in net realized investment gains. In addition, unrealized gains from other changes in total OTTI of $42 million, $55 million and $33 million for the years ended December 31, 2012, 2011 and 2010, respectively, were recognized in other comprehensive income as part of changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income.