Consolidating Financial Statements (details) - Consolidating Statement of Cash Flows (Unaudited) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2016	Sep. 30, 2015	Sep. 30, 2016	Sep. 30, 2015
Consolidating Statement of Cash Flows
Net income	$ 716	$ 928	$ 2,071	$ 2,573
Net adjustments to reconcile net income to net cash provided by operating activities			992	101
Net cash provided by operating activities			3,063	2,674
Proceeds from maturities of fixed maturities			6,648	8,805
Proceeds from sales of investments, fixed maturities			865	1,555
Proceeds from sales of investments, equity securities			71	38
Proceeds from sales of investments, real estate investments			69	15
Proceeds from sales of investments, other investments			569	505
Purchases of investments, fixed maturities			(9,004)	(9,972)
Purchases of investments, equity securities			(36)	(31)
Purchases of investments, real estate investments			(30)	(116)
Purchases of investments, other investments			(422)	(389)
Net (purchases) sales of short-term securities			(135)	(782)
Securities transactions in course of settlement			511	103
Other investing activities			(240)	(222)
Net cash used in investing activities			(1,134)	(491)
Treasury stock acquired - share repurchase authorization			(1,650)	(2,150)
Treasury stock acquired - net employee share-based compensation			(71)	(73)
Dividends paid to shareholders			(569)	(557)
Payment of debt			(400)
Issuance of debt			491	392
Issuance of common stock - employee share options			164	142
Excess tax benefits from share-based payment arrangements				42
Net cash used in financing activities			(2,035)	(2,204)
Effect of exchange rate changes on cash			(5)	(9)
Net decrease in cash			(111)	(30)
Cash at beginning of year			380	374
Cash at end of period	269	344	269	344
Income taxes paid (received)			648	882
Interest paid			223	217
TPC [Member]
Consolidating Statement of Cash Flows
Net income	538	699	1,565	1,959
Net adjustments to reconcile net income to net cash provided by operating activities			643	90
Net cash provided by operating activities			2,208	2,049
Proceeds from maturities of fixed maturities			4,854	5,929
Proceeds from sales of investments, fixed maturities			458	935
Proceeds from sales of investments, equity securities			39	14
Proceeds from sales of investments, other investments			399	341
Purchases of investments, fixed maturities			(6,016)	(6,845)
Purchases of investments, equity securities			(5)	(3)
Purchases of investments, real estate investments			(1)
Purchases of investments, other investments			(328)	(311)
Net (purchases) sales of short-term securities			(339)	(172)
Securities transactions in course of settlement			422	80
Other investing activities			(236)	(262)
Net cash used in investing activities			(753)	(294)
Dividends paid to parent company			(1,550)	(1,774)
Net cash used in financing activities			(1,550)	(1,774)
Effect of exchange rate changes on cash			1	(1)
Net decrease in cash			(94)	(20)
Cash at beginning of year			225	221
Cash at end of period	131	201	131	201
Income taxes paid (received)			536	748
Interest paid			40	40
Other Subsidiaries [Member]
Consolidating Statement of Cash Flows
Net income	213	287	621	787
Net adjustments to reconcile net income to net cash provided by operating activities			92	(247)
Net cash provided by operating activities			713	540
Proceeds from maturities of fixed maturities			1,788	2,869
Proceeds from sales of investments, fixed maturities			405	620
Proceeds from sales of investments, equity securities			32	24
Proceeds from sales of investments, real estate investments			69	15
Proceeds from sales of investments, other investments			170	164
Purchases of investments, fixed maturities			(2,978)	(3,103)
Purchases of investments, equity securities			(29)	(26)
Purchases of investments, real estate investments			(29)	(116)
Purchases of investments, other investments			(94)	(78)
Net (purchases) sales of short-term securities			366	(184)
Securities transactions in course of settlement			86	23
Other investing activities			(4)	40
Net cash used in investing activities			(218)	248
Dividends paid to parent company			(506)	(790)
Net cash used in financing activities			(506)	(790)
Effect of exchange rate changes on cash			(6)	(8)
Net decrease in cash			(17)	(10)
Cash at beginning of year			153	151
Cash at end of period	136	141	136	141
Income taxes paid (received)			206	286
TRV [Member]
Consolidating Statement of Cash Flows
Net income	716	928	2,071	2,573
Net adjustments to reconcile net income to net cash provided by operating activities			127	76
Net cash provided by operating activities			2,198	2,649
Proceeds from maturities of fixed maturities			6	7
Proceeds from sales of investments, fixed maturities			2
Purchases of investments, fixed maturities			(10)	(24)
Purchases of investments, equity securities			(2)	(2)
Net (purchases) sales of short-term securities			(162)	(426)
Securities transactions in course of settlement			3
Net cash used in investing activities			(163)	(445)
Treasury stock acquired - share repurchase authorization			(1,650)	(2,150)
Treasury stock acquired - net employee share-based compensation			(71)	(73)
Dividends paid to shareholders			(569)	(557)
Payment of debt			(400)
Issuance of debt			491	392
Issuance of common stock - employee share options			164	142
Excess tax benefits from share-based payment arrangements				42
Net cash used in financing activities			(2,035)	(2,204)
Cash at beginning of year			2	2
Cash at end of period	2	2	2	2
Income taxes paid (received)			(94)	(152)
Interest paid			183	177
Eliminations [Member]
Consolidating Statement of Cash Flows
Net income	$ (751)	$ (986)	(2,186)	(2,746)
Net adjustments to reconcile net income to net cash provided by operating activities			130	182
Net cash provided by operating activities			(2,056)	(2,564)
Dividends paid to parent company			2,056	2,564
Net cash used in financing activities			$ 2,056	$ 2,564