Consolidating Financial Statements (details) - Consolidating Statement of Income (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended								12 Months Ended
	Dec. 31, 2014	Sep. 30, 2014	Jun. 30, 2014	Mar. 31, 2014	Dec. 31, 2013	Sep. 30, 2013	Jun. 30, 2013	Mar. 31, 2013	Dec. 31, 2014		Dec. 31, 2013		Dec. 31, 2012
Consolidating Statement of Income
Premiums									$ 23,713		$ 22,637		$ 22,357
Net investment income									2,787		2,716		2,889
Fee income									438		395		323
Net realized investment gains									79	[1]	166	[1]	51	[1]
Other revenues									145		277		120
Total revenues	6,783	6,886	6,785	6,708	6,737	6,452	6,674	6,328	27,162		26,191		25,740
Claims and claim adjustment expenses									13,870		13,307		14,676
Amortization of deferred acquisition costs									3,882		3,821		3,910
General and administrative expenses									3,952		3,757		3,610
Interest expense									369		361		378
Total claims and expenses	5,323	5,628	5,884	5,238	5,366	5,275	5,497	5,108	22,073		21,246		22,574
Income before income taxes	1,460	1,258	901	1,470	1,371	1,177	1,177	1,220	5,089		4,945		3,166
Income tax expense (benefit)	422	339	218	418	383	313	252	324	1,397		1,272		693
Net income	1,038	919	683	1,052	988	864	925	896	3,692		3,673		2,473
Total other-than-temporary impairment gains (losses)									(22)		(10)		27
Other-than-temporary impairment losses recognized in net realized investment gains									(26)		(15)		(15)
Other-than-temporary impairment gains recognized in other comprehensive income									4		5		42
Reportable Legal Entities [Member] | TPC [Member]
Consolidating Statement of Income
Premiums									16,097		15,262		15,158
Net investment income									1,874		1,830		1,912
Fee income									436		393		321
Net realized investment gains									12		126		29
Other revenues									125		225		87
Total revenues									18,544		17,836		17,507
Claims and claim adjustment expenses									9,274		8,817		9,908
Amortization of deferred acquisition costs									2,604		2,571		2,636
General and administrative expenses									2,743		2,570		2,445
Interest expense									48		53		73
Total claims and expenses									14,669		14,011		15,062
Income before income taxes									3,875		3,825		2,445
Income tax expense (benefit)									1,095		1,054		588
Net income									2,780		2,771		1,857
Total other-than-temporary impairment gains (losses)									(16)		(8)		18
Other-than-temporary impairment losses recognized in net realized investment gains									(19)		(10)		(9)
Other-than-temporary impairment gains recognized in other comprehensive income									3		2		27
Reportable Legal Entities [Member] | Other Subsidiaries [Member]
Consolidating Statement of Income
Premiums									7,616		7,375		7,199
Net investment income									907		879		968
Fee income									2		2		2
Net realized investment gains									64		38		22
Other revenues									20		52		34
Total revenues									8,609		8,346		8,225
Claims and claim adjustment expenses									4,596		4,490		4,768
Amortization of deferred acquisition costs									1,278		1,250		1,274
General and administrative expenses									1,194		1,174		1,161
Total claims and expenses									7,068		6,914		7,203
Income before income taxes									1,541		1,432		1,022
Income tax expense (benefit)									417		388		224
Net income									1,124		1,044		798
Total other-than-temporary impairment gains (losses)									(6)		(2)		9
Other-than-temporary impairment losses recognized in net realized investment gains									(7)		(5)		(6)
Other-than-temporary impairment gains recognized in other comprehensive income									1		3		15
Reportable Legal Entities [Member] | Travelers [Member]
Consolidating Statement of Income
Net investment income									6		7		9
Net realized investment gains									3		2
Other revenues													(1)
Total revenues									9		9		8
General and administrative expenses									15		13		4
Interest expense									321		308		305
Total claims and expenses									336		321		309
Income before income taxes									(327)		(312)		(301)
Income tax expense (benefit)									(115)		(170)		(119)
Net income of subsidiaries									3,904		3,815		2,655
Net income									3,692		3,673		2,473
Other-than-temporary impairment losses recognized in net realized investment gains									0		0		0
Other-than-temporary impairment gains recognized in other comprehensive income									0		0		0
Eliminations [Member]
Consolidating Statement of Income
Net income of subsidiaries									(3,904)		(3,815)		(2,655)
Net income									$ (3,904)		$ (3,815)		$ (2,655)

[1] Total other-than-temporary impairment (OTTI) gains (losses) were $(22) million, $(10) million and $27 million for the years ended December 31, 2014, 2013 and 2012, respectively. Of total OTTI, credit losses of $(26) million, $(15) million and $(15) million for the years ended December 31, 2014, 2013 and 2012 respectively, were recognized in net realized investment gains. In addition, unrealized gains from other changes in total OTTI of $4 million, $5 million and $42 million for the years ended December 31, 2014, 2013 and 2012, 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.