Consolidating Financial Statements (details) - Consolidating Balance Sheet (Unaudited) - USD ($) shares in Millions, $ in Millions	Jun. 30, 2016	Dec. 31, 2015	Jun. 30, 2015	Dec. 31, 2014
Consolidating Balance Sheet
Fixed maturities, available for sale, at fair value	$ 63,311	$ 60,658
Equity securities, available for sale, at fair value	752	705
Real estate investments	929	989
Short-term securities	3,988	4,671
Other investments	3,490	3,447
Total investments	72,470	70,470
Cash	265	380	$ 317	$ 374
Investment income accrued	627	642
Premiums receivable	7,014	6,437
Reinsurance recoverables	8,603	8,910
Ceded unearned premiums	726	656
Deferred acquisition costs	1,954	1,849
Deferred taxes		296
Contractholder receivables	4,541	4,374
Goodwill	3,588	3,573
Other intangible assets	274	279
Other assets	2,384	2,318
Total assets	102,446	100,184
Claims and claim adjustment expense reserves	47,953	48,295
Unearned premium reserves	12,520	11,971
Contractholder payables	4,541	4,374
Payables for reinsurance premiums	401	296
Deferred taxes	370
Debt	6,436	6,344
Other liabilities	5,511	5,306
Total liabilities	77,732	76,586
Common stock	22,349	22,172
Retained earnings	30,921	29,945
Accumulated other comprehensive income (loss)	965	(157)
Treasury stock, at cost	(29,521)	(28,362)
Total shareholders' equity	24,714	23,598	24,121
Total liabilities and shareholders' equity	102,446	100,184
Fixed maturities, available for sale, amortized cost	59,975	58,878
Equity securities, available for sale, cost	$ 525	$ 528
Common stock, shares authorized	1,750.0	1,750.0
Common stock, shares issued	288.3	295.9
Common stock, shares outstanding	288.3	295.9
Treasury stock, at cost, shares	478.1	467.6
TPC [Member]
Consolidating Balance Sheet
Fixed maturities, available for sale, at fair value	$ 43,859	$ 42,289
Equity securities, available for sale, at fair value	194	189
Real estate investments	55	56
Short-term securities	1,754	1,947
Other investments	2,594	2,516
Total investments	48,456	46,997
Cash	121	225	184	221
Investment income accrued	441	453
Premiums receivable	4,722	4,336
Reinsurance recoverables	5,928	5,849
Ceded unearned premiums	649	610
Deferred acquisition costs	1,753	1,660
Deferred taxes		178
Contractholder receivables	3,570	3,387
Goodwill	2,584	2,573
Other intangible assets	203	203
Other assets	2,106	1,958
Total assets	70,533	68,429
Claims and claim adjustment expense reserves	32,096	31,965
Unearned premium reserves	8,708	8,335
Contractholder payables	3,570	3,387
Payables for reinsurance premiums	227	175
Deferred taxes	330
Debt	693	693
Other liabilities	4,188	3,958
Total liabilities	49,812	48,513
Additional paid-in capital	11,634	11,634
Retained earnings	7,890	7,888
Accumulated other comprehensive income (loss)	1,197	394
Total shareholders' equity	20,721	19,916
Total liabilities and shareholders' equity	70,533	68,429
Other Subsidiaries [Member]
Consolidating Balance Sheet
Fixed maturities, available for sale, at fair value	19,403	18,323
Equity securities, available for sale, at fair value	412	375
Real estate investments	874	933
Short-term securities	537	1,178
Other investments	895	930
Total investments	22,121	21,739
Cash	141	153	131	151
Investment income accrued	182	185
Premiums receivable	2,292	2,101
Reinsurance recoverables	2,675	3,061
Ceded unearned premiums	77	46
Deferred acquisition costs	201	189
Deferred taxes		83
Contractholder receivables	971	987
Goodwill	1,004	1,000
Other intangible assets	71	76
Other assets	(52)	344
Total assets	29,683	29,964
Claims and claim adjustment expense reserves	15,857	16,330
Unearned premium reserves	3,812	3,636
Contractholder payables	971	987
Payables for reinsurance premiums	174	121
Deferred taxes	118
Other liabilities	707	1,221
Total liabilities	21,639	22,295
Common stock	390	390
Additional paid-in capital	6,499	6,499
Retained earnings	744	688
Accumulated other comprehensive income (loss)	411	92
Total shareholders' equity	8,044	7,669
Total liabilities and shareholders' equity	29,683	29,964
TRV [Member]
Consolidating Balance Sheet
Fixed maturities, available for sale, at fair value	49	46
Equity securities, available for sale, at fair value	146	141
Short-term securities	1,697	1,546
Other investments	1	1
Total investments	1,893	1,734
Cash	3	2	$ 2	$ 2
Investment income accrued	4	4
Deferred taxes		35
Investment in subsidiaries	28,755	27,573
Other assets	330	16
Total assets	30,985	29,364
Deferred taxes	(78)
Debt	5,743	5,651
Other liabilities	616	127
Total liabilities	6,281	5,778
Common stock	22,349	22,172
Retained earnings	30,911	29,933
Accumulated other comprehensive income (loss)	965	(157)
Treasury stock, at cost	(29,521)	(28,362)
Total shareholders' equity	24,704	23,586
Total liabilities and shareholders' equity	30,985	29,364
Eliminations [Member]
Consolidating Balance Sheet
Investment in subsidiaries	(28,755)	(27,573)
Total assets	(28,755)	(27,573)
Common stock	(390)	(390)
Additional paid-in capital	(18,133)	(18,133)
Retained earnings	(8,624)	(8,564)
Accumulated other comprehensive income (loss)	(1,608)	(486)
Total shareholders' equity	(28,755)	(27,573)
Total liabilities and shareholders' equity	$ (28,755)	$ (27,573)