Consolidating Financial Statements (details) - Consolidating Statement of Cash Flows (Unaudited) (USD $) In Millions, unless otherwise specified	3 Months Ended
	Mar. 31, 2014	Mar. 31, 2013
Consolidating Statement of Cash Flows
Net income	$ 1,052	$ 896
Net adjustments to reconcile net income to net cash provided by (used in) operating activities	(349)	(366)
Net cash provided by operating activities	703	530
Proceeds from maturities of fixed maturities	2,312	2,123
Proceeds from sales of investments, fixed maturities	406	234
Proceeds from sales of investments, equity securities	36	36
Proceeds from sales of investments, real estate investments	1
Proceeds from sales of investments, other investments	167	174
Purchases of investments, fixed maturities	(2,715)	(2,339)
Purchases of investments, equity securities	(18)	(13)
Purchases of investments, real estate investments	(9)	(6)
Purchases of investments, other investments	(113)	(95)
Net (purchases) sales of short-term securities	(160)	109
Securities transactions in course of settlement	240	180
Acquisition, net of cash acquired	(12)
Other investing activities	(60)	(100)
Net cash provided by investing activities	75	303
Payment of debt		(500)
Dividends paid to shareholders	(176)	(175)
Issuance of common stock - employee share options	57	98
Treasury stock acquired - share repurchase authorization	(650)	(300)
Treasury stock acquired - net employee share-based compensation	(54)	(58)
Excess tax benefits from share-based payment arrangements	13	21
Net cash used in financing activities	(810)	(914)
Effect of exchange rate changes on cash	(2)	(6)
Net decrease in cash	(34)	(87)
Cash at beginning of year	294	330
Cash at end of period	260	243
Income taxes paid (received)	93	27
Interest paid	34	35
Reportable Legal Entities [Member] | TPC [Member]
Consolidating Statement of Cash Flows
Net income	783	650
Net adjustments to reconcile net income to net cash provided by (used in) operating activities	(90)	(251)
Net cash provided by operating activities	693	399
Proceeds from maturities of fixed maturities	1,334	1,345
Proceeds from sales of investments, fixed maturities	192	170
Proceeds from sales of investments, equity securities	22	10
Proceeds from sales of investments, other investments	100	101
Purchases of investments, fixed maturities	(1,681)	(1,453)
Purchases of investments, equity securities	(1)	(5)
Purchases of investments, other investments	(74)	(62)
Net (purchases) sales of short-term securities	(73)	(326)
Securities transactions in course of settlement	183	95
Acquisition, net of cash acquired	(9)
Other investing activities	(58)	(99)
Net cash provided by investing activities	(65)	(224)
Payment of debt		(500)
Capital contributions		500
Dividends paid to parent company	(625)	(217)
Net cash used in financing activities	(625)	(217)
Effect of exchange rate changes on cash	(1)
Net decrease in cash	2	(42)
Cash at beginning of year	137	177
Cash at end of period	139	135
Income taxes paid (received)	64	97
Interest paid	16	28
Reportable Legal Entities [Member] | Other Subsidiaries [Member]
Consolidating Statement of Cash Flows
Net income	321	293
Net adjustments to reconcile net income to net cash provided by (used in) operating activities	(315)	(276)
Net cash provided by operating activities	6	17
Proceeds from maturities of fixed maturities	977	778
Proceeds from sales of investments, fixed maturities	214	60
Proceeds from sales of investments, equity securities	10	26
Proceeds from sales of investments, real estate investments	1
Proceeds from sales of investments, other investments	67	73
Purchases of investments, fixed maturities	(1,030)	(886)
Purchases of investments, equity securities	(13)	(8)
Purchases of investments, real estate investments	(9)	(6)
Purchases of investments, other investments	(39)	(33)
Net (purchases) sales of short-term securities	(37)	(43)
Securities transactions in course of settlement	56	85
Acquisition, net of cash acquired	(3)
Other investing activities	(2)	(1)
Net cash provided by investing activities	192	45
Dividends paid to parent company	(232)	(100)
Net cash used in financing activities	(232)	(100)
Effect of exchange rate changes on cash	(1)	(6)
Net decrease in cash	(35)	(44)
Cash at beginning of year	154	151
Cash at end of period	119	107
Income taxes paid (received)	15	24
Reportable Legal Entities [Member] | Travelers [Member]
Consolidating Statement of Cash Flows
Net income	1,052	896
Net adjustments to reconcile net income to net cash provided by (used in) operating activities	(191)	(965)
Net cash provided by operating activities	861	(69)
Proceeds from maturities of fixed maturities	1
Proceeds from sales of investments, fixed maturities		4
Proceeds from sales of investments, equity securities	4
Purchases of investments, fixed maturities	(4)
Purchases of investments, equity securities	(4)
Net (purchases) sales of short-term securities	(50)	478
Securities transactions in course of settlement	1
Net cash provided by investing activities	(52)	482
Dividends paid to shareholders	(176)	(175)
Issuance of common stock - employee share options	57	98
Treasury stock acquired - share repurchase authorization	(650)	(300)
Treasury stock acquired - net employee share-based compensation	(54)	(58)
Excess tax benefits from share-based payment arrangements	13	21
Net cash used in financing activities	(810)	(414)
Net decrease in cash	(1)	(1)
Cash at beginning of year	3	2
Cash at end of period	2	1
Income taxes paid (received)	14	(94)
Interest paid	18	7
Eliminations [Member]
Consolidating Statement of Cash Flows
Net income	(1,104)	(943)
Net adjustments to reconcile net income to net cash provided by (used in) operating activities	247	1,126
Net cash provided by operating activities	(857)	183
Capital contributions		(500)
Dividends paid to parent company	857	317
Net cash used in financing activities	$ 857	$ (183)