Consolidating Financial Statements (details) - Consolidating Statement of Cash Flows (Unaudited) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Consolidating financial statements
Net income	$ 2,473	$ 1,426	$ 3,216
Net adjustments to reconcile net income to net cash provided by operating activities	757	743	(162)
Net cash provided by operating activities	3,230	2,169	3,054
Proceeds from maturities of fixed maturities	8,369	7,404	5,896
Proceeds from sales of investments, fixed maturities	1,087	1,161	3,713
Proceeds from sales of investments, equity securities	37	135	201
Proceeds from sales of investments, real estate investments	53	1	10
Proceeds from sales of investments, other investments	835	594	717
Purchases of investments, fixed maturities	(10,447)	(8,704)	(6,785)
Purchases of investments, equity securities	(48)	(131)	(61)
Purchases of investments, real estate investments	(95)	(66)	(21)
Purchases of investments, other investments	(534)	(889)	(514)
Net sales (purchases) of short-term securities	117	2,018	(699)
Securities transactions in course of settlement	(23)		(30)
Other investing activities	(323)	(371)	(318)
Net cash provided by (used in) investing activities	(972)	1,152	2,109
Payment of debt	(258)	(8)	(1,160)
Issuance of debt			1,234
Dividends paid to shareholders	(694)	(665)	(673)
Issuance of common stock - employee share options	295	314	408
Treasury stock acquired - share repurchase authorization	(1,474)	(2,919)	(4,998)
Treasury stock acquired - net employee share-based compensation	(53)	(46)	(40)
Excess tax benefits from share-based payment arrangements	38	18	8
Net cash used in financing activities	(2,146)	(3,306)	(5,221)
Effect of exchange rate changes on cash	4	(1)	3
Net increase (decrease) in cash	116	14	(55)
Cash at beginning of year	214	200	255
Cash at end of year	330	214	200
Income taxes paid (received)	188	218	784
Interest paid	375	382	397
TPC [Member]
Consolidating financial statements
Net income	1,857	1,182	2,464
Net adjustments to reconcile net income to net cash provided by operating activities	715	736	(77)
Net cash provided by operating activities	2,572	1,918	2,387
Proceeds from maturities of fixed maturities	5,905	4,902	3,920
Proceeds from sales of investments, fixed maturities	730	720	2,289
Proceeds from sales of investments, equity securities	21	82	29
Proceeds from sales of investments, real estate investments		1
Proceeds from sales of investments, other investments	555	343	338
Purchases of investments, fixed maturities	(7,361)	(5,714)	(4,201)
Purchases of investments, equity securities	(18)	(30)	(2)
Purchases of investments, real estate investments		(24)
Purchases of investments, other investments	(371)	(711)	(305)
Net sales (purchases) of short-term securities	(308)	717	632
Securities transactions in course of settlement	14	(46)	(4)
Other investing activities	(323)	(351)	(313)
Net cash provided by (used in) investing activities	(1,156)	(111)	2,383
Payment of debt			(4)
Dividends paid to parent company	(1,353)	(1,779)	(4,827)
Capital contributions, loans and other transactions between subsidiaries			15
Net cash used in financing activities	(1,353)	(1,779)	(4,816)
Net increase (decrease) in cash	63	28	(46)
Cash at beginning of year	114	86	132
Cash at end of year	177	114	86
Income taxes paid (received)	287	206	579
Interest paid	73	73	73
Other Subsidiaries [Member]
Consolidating financial statements
Net income	798	382	1,033
Net adjustments to reconcile net income to net cash provided by operating activities	7	98	(514)
Net cash provided by operating activities	805	480	519
Proceeds from maturities of fixed maturities	2,462	2,502	1,966
Proceeds from sales of investments, fixed maturities	355	440	1,424
Proceeds from sales of investments, equity securities	16	53	148
Proceeds from sales of investments, real estate investments	53		10
Proceeds from sales of investments, other investments	280	251	280
Purchases of investments, fixed maturities	(3,077)	(2,978)	(2,576)
Purchases of investments, equity securities	(28)	(71)	(33)
Purchases of investments, real estate investments	(95)	(42)	(21)
Purchases of investments, other investments	(163)	(178)	(209)
Net sales (purchases) of short-term securities	44	25	392
Securities transactions in course of settlement	(36)	46	(26)
Other investing activities		(20)	(5)
Net cash provided by (used in) investing activities	(189)	28	1,350
Payment of debt		(8)
Dividends paid to parent company	(567)	(521)	(1,849)
Capital contributions, loans and other transactions between subsidiaries		10	(35)
Net cash used in financing activities	(567)	(519)	(1,884)
Effect of exchange rate changes on cash	4	(1)	3
Net increase (decrease) in cash	53	(12)	(12)
Cash at beginning of year	98	110	122
Cash at end of year	151	98	110
Income taxes paid (received)	108	109	321
Travelers [Member]
Consolidating financial statements
Net income	2,473	1,426	3,216
Net adjustments to reconcile net income to net cash provided by operating activities	(700)	635	3,626
Net cash provided by operating activities	1,773	2,061	6,842
Proceeds from maturities of fixed maturities	2		10
Proceeds from sales of investments, fixed maturities	2	1
Proceeds from sales of investments, equity securities			24
Proceeds from sales of investments, other investments			99
Purchases of investments, fixed maturities	(9)	(12)	(8)
Purchases of investments, equity securities	(2)	(30)	(26)
Net sales (purchases) of short-term securities	381	1,276	(1,723)
Securities transactions in course of settlement	(1)
Net cash provided by (used in) investing activities	373	1,235	(1,624)
Payment of debt	(258)		(1,156)
Issuance of debt			1,234
Dividends paid to shareholders	(694)	(665)	(673)
Issuance of common stock - employee share options	295	314	408
Treasury stock acquired - share repurchase authorization	(1,474)	(2,919)	(4,998)
Treasury stock acquired - net employee share-based compensation	(53)	(46)	(40)
Excess tax benefits from share-based payment arrangements	38	18	8
Capital contributions, loans and other transactions between subsidiaries			2
Net cash used in financing activities	(2,146)	(3,298)	(5,215)
Net increase (decrease) in cash		(2)	3
Cash at beginning of year	2	4	1
Cash at end of year	2	2	4
Income taxes paid (received)	(207)	(97)	(116)
Interest paid	302	309	324
Eliminations [Member]
Consolidating financial statements
Net income	(2,655)	(1,564)	(3,497)
Net adjustments to reconcile net income to net cash provided by operating activities	735	(726)	(3,197)
Net cash provided by operating activities	(1,920)	(2,290)	(6,694)
Dividends paid to parent company	1,920	2,300	6,676
Capital contributions, loans and other transactions between subsidiaries		(10)	18
Net cash used in financing activities	$ 1,920	$ 2,290	$ 6,694