Consolidating Financial Statements (details) - Consolidating Statement of Cash Flows (Unaudited) (USD $) In Millions, unless otherwise specified	6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012
Consolidating Statement of Cash Flows
Net income	$ 1,821	$ 1,305
Net adjustments to reconcile net income to net cash provided by operating activities	(569)	(40)
Net cash provided by operating activities	1,252	1,265
Proceeds from maturities of fixed maturities	3,901	4,167
Proceeds from sales of investments, fixed maturities	572	542
Proceeds from sales of investments, equity securities	50	22
Proceeds from sales of investments, real estate investments		3
Proceeds from sales of investments, other investments	381	386
Purchases of investments, fixed maturities	(4,488)	(5,200)
Purchases of investments, equity securities	(40)	(33)
Purchases of investments, real estate investments	(59)	(58)
Purchases of investments, other investments	(209)	(221)
Net sales (purchases) of short-term securities	81	367
Securities transactions in course of settlement	60	77
Other investing activities	(157)	(133)
Net cash provided by (used in) investing activities	92	(81)
Payment of debt	(500)	(258)
Dividends paid to shareholders	(366)	(341)
Issuance of common stock - employee share options	139	170
Treasury stock acquired - share repurchase authorization	(600)	(707)
Treasury stock acquired - net employee share-based compensation	(59)	(52)
Excess tax benefits from share-based payment arrangements	29	19
Net cash used in financing activities	(1,357)	(1,169)
Effect of exchange rate changes on cash	(9)	1
Net increase (decrease) in cash	(22)	16
Cash at beginning of year	330	214
Cash at end of period	308	230
Income taxes paid (received)	495	296
Interest paid	184	191
TPC [Member]
Consolidating Statement of Cash Flows
Net income	1,392	1,012
Net adjustments to reconcile net income to net cash provided by operating activities	(807)	109
Net cash provided by operating activities	585	1,121
Proceeds from maturities of fixed maturities	2,570	2,817
Proceeds from sales of investments, fixed maturities	300	368
Proceeds from sales of investments, equity securities	18	15
Proceeds from sales of investments, other investments	224	297
Purchases of investments, fixed maturities	(3,062)	(3,744)
Purchases of investments, equity securities	(15)	(2)
Purchases of investments, other investments	(150)	(139)
Net sales (purchases) of short-term securities	(182)	(176)
Securities transactions in course of settlement	59	87
Other investing activities	(155)	(144)
Net cash provided by (used in) investing activities	(393)	(621)
Payment of debt	(500)
Capital contributions	500
Dividends paid to parent company	(217)	(504)
Net cash used in financing activities	(217)	(504)
Net increase (decrease) in cash	(25)	(4)
Cash at beginning of year	177	114
Cash at end of period	152	110
Income taxes paid (received)	479	286
Interest paid	36	36
Other Subsidiaries [Member]
Consolidating Statement of Cash Flows
Net income	524	394
Net adjustments to reconcile net income to net cash provided by operating activities	37	(283)
Net cash provided by operating activities	561	111
Proceeds from maturities of fixed maturities	1,330	1,350
Proceeds from sales of investments, fixed maturities	267	173
Proceeds from sales of investments, equity securities	32	7
Proceeds from sales of investments, real estate investments		3
Proceeds from sales of investments, other investments	157	89
Purchases of investments, fixed maturities	(1,419)	(1,454)
Purchases of investments, equity securities	(24)	(30)
Purchases of investments, real estate investments	(59)	(58)
Purchases of investments, other investments	(59)	(82)
Net sales (purchases) of short-term securities	78	115
Securities transactions in course of settlement	1	(10)
Other investing activities	(2)	11
Net cash provided by (used in) investing activities	302	114
Dividends paid to parent company	(850)	(208)
Net cash used in financing activities	(850)	(208)
Effect of exchange rate changes on cash	(9)	1
Net increase (decrease) in cash	4	18
Cash at beginning of year	151	98
Cash at end of period	155	116
Income taxes paid (received)	178	113
Travelers [Member]
Consolidating Statement of Cash Flows
Net income	1,821	1,305
Net adjustments to reconcile net income to net cash provided by operating activities	(1,148)	(560)
Net cash provided by operating activities	673	745
Proceeds from maturities of fixed maturities	1
Proceeds from sales of investments, fixed maturities	5	1
Purchases of investments, fixed maturities	(7)	(2)
Purchases of investments, equity securities	(1)	(1)
Net sales (purchases) of short-term securities	185	428
Net cash provided by (used in) investing activities	183	426
Payment of debt		(258)
Dividends paid to shareholders	(366)	(341)
Issuance of common stock - employee share options	139	170
Treasury stock acquired - share repurchase authorization	(600)	(707)
Treasury stock acquired - net employee share-based compensation	(59)	(52)
Excess tax benefits from share-based payment arrangements	29	19
Net cash used in financing activities	(857)	(1,169)
Net increase (decrease) in cash	(1)	2
Cash at beginning of year	2	2
Cash at end of period	1	4
Income taxes paid (received)	(162)	(103)
Interest paid	148	155
Eliminations [Member]
Consolidating Statement of Cash Flows
Net income	(1,916)	(1,406)
Net adjustments to reconcile net income to net cash provided by operating activities	1,349	694
Net cash provided by operating activities	(567)	(712)
Capital contributions	(500)
Dividends paid to parent company	1,067	712
Net cash used in financing activities	$ 567	$ 712