Consolidating Financial Statements (details) - Consolidating Balance Sheet (Unaudited) - USD ($) shares in Millions, $ in Millions	Sep. 30, 2016	Dec. 31, 2015	Sep. 30, 2015	Dec. 31, 2014
Consolidating Balance Sheet
Fixed maturities, available for sale, at fair value	$ 63,036	$ 60,658
Equity securities, available for sale, at fair value	744	705
Real estate investments	929	989
Short-term securities	4,803	4,671
Other investments	3,452	3,447
Total investments	72,964	70,470
Cash	269	380	$ 344	$ 374
Investment income accrued	586	642
Premiums receivable	6,785	6,437
Reinsurance recoverables	8,665	8,910
Ceded unearned premiums	741	656
Deferred acquisition costs	1,975	1,849
Deferred taxes		296
Contractholder receivables	4,580	4,374
Goodwill	3,585	3,573
Other intangible assets	271	279
Other assets	2,366	2,318
Total assets	102,787	100,184
Claims and claim adjustment expense reserves	48,168	48,295
Unearned premium reserves	12,706	11,971
Contractholder payables	4,580	4,374
Payables for reinsurance premiums	431	296
Deferred taxes	171
Debt	6,436	6,344
Other liabilities	5,856	5,306
Total liabilities	78,348	76,586
Common stock	22,419	22,172
Retained earnings	31,443	29,945
Accumulated other comprehensive income (loss)	660	(157)
Treasury stock, at cost	(30,083)	(28,362)
Total shareholders' equity	24,439	23,598	24,033
Total liabilities and shareholders' equity	102,787	100,184
Fixed maturities, available for sale, amortized cost	60,149	58,878
Equity securities, available for sale, cost	$ 510	$ 528
Common stock, shares authorized	1,750.0	1,750.0
Common stock, shares issued	284.1	295.9
Common stock, shares outstanding	284.1	295.9
Treasury stock, at cost, shares	482.9	467.6
TPC [Member]
Consolidating Balance Sheet
Fixed maturities, available for sale, at fair value	$ 43,726	$ 42,289
Equity securities, available for sale, at fair value	174	189
Real estate investments	55	56
Short-term securities	2,286	1,947
Other investments	2,572	2,516
Total investments	48,813	46,997
Cash	131	225	201	221
Investment income accrued	408	453
Premiums receivable	4,594	4,336
Reinsurance recoverables	5,991	5,849
Ceded unearned premiums	669	610
Deferred acquisition costs	1,786	1,660
Deferred taxes		178
Contractholder receivables	3,613	3,387
Goodwill	2,583	2,573
Other intangible assets	203	203
Other assets	1,945	1,958
Total assets	70,736	68,429
Claims and claim adjustment expense reserves	32,282	31,965
Unearned premium reserves	8,880	8,335
Contractholder payables	3,613	3,387
Payables for reinsurance premiums	255	175
Deferred taxes	175
Debt	692	693
Other liabilities	4,317	3,958
Total liabilities	50,214	48,513
Additional paid-in capital	11,634	11,634
Retained earnings	7,903	7,888
Accumulated other comprehensive income (loss)	985	394
Total shareholders' equity	20,522	19,916
Total liabilities and shareholders' equity	70,736	68,429
Other Subsidiaries [Member]
Consolidating Balance Sheet
Fixed maturities, available for sale, at fair value	19,260	18,323
Equity securities, available for sale, at fair value	419	375
Real estate investments	874	933
Short-term securities	809	1,178
Other investments	879	930
Total investments	22,241	21,739
Cash	136	153	141	151
Investment income accrued	174	185
Premiums receivable	2,191	2,101
Reinsurance recoverables	2,674	3,061
Ceded unearned premiums	72	46
Deferred acquisition costs	189	189
Deferred taxes		83
Contractholder receivables	967	987
Goodwill	1,002	1,000
Other intangible assets	68	76
Other assets	404	344
Total assets	30,118	29,964
Claims and claim adjustment expense reserves	15,886	16,330
Unearned premium reserves	3,826	3,636
Contractholder payables	967	987
Payables for reinsurance premiums	176	121
Deferred taxes	76
Other liabilities	1,191	1,221
Total liabilities	22,122	22,295
Common stock	390	390
Additional paid-in capital	6,499	6,499
Retained earnings	800	688
Accumulated other comprehensive income (loss)	307	92
Total shareholders' equity	7,996	7,669
Total liabilities and shareholders' equity	30,118	29,964
TRV [Member]
Consolidating Balance Sheet
Fixed maturities, available for sale, at fair value	50	46
Equity securities, available for sale, at fair value	151	141
Short-term securities	1,708	1,546
Other investments	1	1
Total investments	1,910	1,734
Cash	2	2	$ 2	$ 2
Investment income accrued	4	4
Deferred taxes		35
Investment in subsidiaries	28,508	27,573
Other assets	17	16
Total assets	30,441	29,364
Deferred taxes	(80)
Debt	5,744	5,651
Other liabilities	348	127
Total liabilities	6,012	5,778
Common stock	22,419	22,172
Retained earnings	31,433	29,933
Accumulated other comprehensive income (loss)	660	(157)
Treasury stock, at cost	(30,083)	(28,362)
Total shareholders' equity	24,429	23,586
Total liabilities and shareholders' equity	30,441	29,364
Eliminations [Member]
Consolidating Balance Sheet
Investment in subsidiaries	(28,508)	(27,573)
Total assets	(28,508)	(27,573)
Common stock	(390)	(390)
Additional paid-in capital	(18,133)	(18,133)
Retained earnings	(8,693)	(8,564)
Accumulated other comprehensive income (loss)	(1,292)	(486)
Total shareholders' equity	(28,508)	(27,573)
Total liabilities and shareholders' equity	$ (28,508)	$ (27,573)