Consolidating Financial Statements (details) - Consolidating Statement of Cash Flows (Unaudited) (USD $) In Millions, unless otherwise specified	9 Months Ended
	Sep. 30, 2014	Sep. 30, 2013
Consolidating Statement of Cash Flows
Net income	$ 2,654	$ 2,685
Net adjustments to reconcile net income to net cash provided by operating activities	514	204
Net cash provided by operating activities	3,168	2,889
Proceeds from maturities of fixed maturities	7,975	5,917
Proceeds from sales of investments, fixed maturities	927	1,160
Proceeds from sales of investments, equity securities	128	57
Proceeds from sales of investments, real estate investments	5
Proceeds from sales of investments, other investments	612	545
Purchases of investments, fixed maturities	(8,237)	(6,492)
Purchases of investments, equity securities	(47)	(50)
Purchases of investments, real estate investments	(41)	(65)
Purchases of investments, other investments	(406)	(312)
Net sales (purchases) of short-term securities	(1,163)	(1,893)
Securities transactions in course of settlement	119	280
Acquisition, net of cash acquired	(12)
Other investing activities	(262)	(254)
Net cash used in investing activities	(402)	(1,107)
Payment of debt		(500)
Issuance of debt		494
Dividends paid to shareholders	(549)	(549)
Issuance of common stock - employee share options	154	158
Treasury stock acquired - share repurchase authorization	(2,275)	(1,400)
Treasury stock acquired - net employee share-based compensation	(56)	(60)
Excess tax benefits from share-based payment arrangements	38	43
Net cash used in financing activities	(2,688)	(1,814)
Effect of exchange rate changes on cash	(5)	(3)
Net increase (decrease) in cash	73	(35)
Cash at beginning of year	294	330
Cash at end of period	367	295
Income taxes paid (received)	785	724
Interest paid	217	206
Reportable Legal Entities [Member] | TPC [Member]
Consolidating Statement of Cash Flows
Net income	1,996	2,056
Net adjustments to reconcile net income to net cash provided by operating activities	391	(348)
Net cash provided by operating activities	2,387	1,708
Proceeds from maturities of fixed maturities	4,886	4,096
Proceeds from sales of investments, fixed maturities	511	590
Proceeds from sales of investments, equity securities	83	21
Proceeds from sales of investments, real estate investments	1
Proceeds from sales of investments, other investments	317	337
Purchases of investments, fixed maturities	(4,888)	(4,339)
Purchases of investments, equity securities	(3)	(20)
Purchases of investments, real estate investments	(22)
Purchases of investments, other investments	(292)	(222)
Net sales (purchases) of short-term securities	(552)	(1,563)
Securities transactions in course of settlement	66	182
Acquisition, net of cash acquired	(9)
Other investing activities	(256)	(250)
Net cash used in investing activities	(158)	(1,168)
Payment of debt		(500)
Capital contributions		500
Dividends paid to parent company	(2,150)	(587)
Net cash used in financing activities	(2,150)	(587)
Net increase (decrease) in cash	79	(47)
Cash at beginning of year	137	177
Cash at end of period	216	130
Income taxes paid (received)	684	691
Interest paid	40	52
Reportable Legal Entities [Member] | Other Subsidiaries [Member]
Consolidating Statement of Cash Flows
Net income	817	775
Net adjustments to reconcile net income to net cash provided by operating activities	(73)	224
Net cash provided by operating activities	744	999
Proceeds from maturities of fixed maturities	3,088	1,820
Proceeds from sales of investments, fixed maturities	415	565
Proceeds from sales of investments, equity securities	41	36
Proceeds from sales of investments, real estate investments	4
Proceeds from sales of investments, other investments	295	208
Purchases of investments, fixed maturities	(3,345)	(2,146)
Purchases of investments, equity securities	(38)	(29)
Purchases of investments, real estate investments	(19)	(65)
Purchases of investments, other investments	(114)	(90)
Net sales (purchases) of short-term securities	(326)	(492)
Securities transactions in course of settlement	53	98
Acquisition, net of cash acquired	(3)
Other investing activities	(6)	(4)
Net cash used in investing activities	45	(99)
Dividends paid to parent company	(789)	(885)
Net cash used in financing activities	(789)	(885)
Effect of exchange rate changes on cash	(5)	(3)
Net increase (decrease) in cash	(5)	12
Cash at beginning of year	154	151
Cash at end of period	149	163
Income taxes paid (received)	215	236
Reportable Legal Entities [Member] | Travelers [Member]
Consolidating Statement of Cash Flows
Net income	2,654	2,685
Net adjustments to reconcile net income to net cash provided by operating activities	322	(1,531)
Net cash provided by operating activities	2,976	1,154
Proceeds from maturities of fixed maturities	1	1
Proceeds from sales of investments, fixed maturities	1	5
Proceeds from sales of investments, equity securities	4
Purchases of investments, fixed maturities	(4)	(7)
Purchases of investments, equity securities	(6)	(1)
Net sales (purchases) of short-term securities	(285)	162
Net cash used in investing activities	(289)	160
Issuance of debt		494
Dividends paid to shareholders	(549)	(549)
Issuance of common stock - employee share options	154	158
Treasury stock acquired - share repurchase authorization	(2,275)	(1,400)
Treasury stock acquired - net employee share-based compensation	(56)	(60)
Excess tax benefits from share-based payment arrangements	38	43
Net cash used in financing activities	(2,688)	(1,314)
Net increase (decrease) in cash	(1)
Cash at beginning of year	3	2
Cash at end of period	2	2
Income taxes paid (received)	(114)	(203)
Interest paid	177	154
Eliminations [Member]
Consolidating Statement of Cash Flows
Net income	(2,813)	(2,831)
Net adjustments to reconcile net income to net cash provided by operating activities	(126)	1,859
Net cash provided by operating activities	(2,939)	(972)
Capital contributions		(500)
Dividends paid to parent company	2,939	1,472
Net cash used in financing activities	$ 2,939	$ 972