Consolidated Statement of Cash Flows - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Cash flows from operating activities
Net income		$ 3,439	$ 3,692	$ 3,673
Adjustments to reconcile net income to net cash provided by operating activities:
Net realized investment gains	[1]	(3)	(79)	(166)
Depreciation and amortization		818	864	867
Deferred federal income tax expense		117	121	167
Amortization of deferred acquisition costs		3,885	3,882	3,821
Equity in income from other investments		(218)	(486)	(357)
Premiums receivable		(185)	(207)	54
Reinsurance recoverables		272	400	1,284
Deferred acquisition costs		(3,920)	(3,926)	(3,759)
Claims and claim adjustment expense reserves		(1,075)	(704)	(2,057)
Unearned premium reserves		248	73	27
Other operating activities		56	63	262
Net cash provided by operating activities		3,434	3,693	3,816
Cash flows from investing activities
Proceeds from maturities of fixed maturities		11,116	10,894	7,904
Proceeds from sales of investments:
Fixed maturities		1,950	1,049	1,635
Equity securities		59	158	86
Real estate investments		31	15	18
Other investments		713	855	762
Purchases of investments:
Fixed maturities		(12,090)	(11,325)	(9,467)
Equity securities		(49)	(52)	(57)
Real estate investments		(123)	(48)	(107)
Other investments		(534)	(554)	(446)
Net sales (purchases) of short-term securities		(326)	(498)	111
Securities transactions in course of settlement		(113)	82	21
Acquisition, net of cash acquired		(13)	(12)	(997)
Other investing activities		(304)	(358)	(373)
Net cash provided by (used in) investing activities		317	206	(910)
Cash flows from financing activities
Treasury stock acquired - share repurchase authorization		(3,150)	(3,275)	(2,400)
Treasury stock acquired - net employee share-based compensation		(74)	(57)	(61)
Dividends paid to shareholders		(739)	(729)	(729)
Payment of debt		(400)		(500)
Issuance of debt		392		494
Issuance of common stock - employee share options		183	195	206
Excess tax benefits from share-based payment arrangements		55	57	51
Net cash used in financing activities		(3,733)	(3,809)	(2,939)
Effect of exchange rate changes on cash		(12)	(10)	(3)
Net increase (decrease) in cash		6	80	(36)
Cash at beginning of year		374	294	330
Cash at end of year		380	374	294
Supplemental disclosure of cash flow information
Income taxes paid		1,207	1,147	1,057
Interest paid		$ 365	$ 365	$ 355

[1] Total other-than-temporary impairment (OTTI) losses were $(54) million, $(22) million and $(10) million for the years ended December 31, 2015, 2014 and 2013, respectively. Of total OTTI, credit losses of $(52) million, $(26) million and $(15) million for the years ended December 31, 2015, 2014 and 2013, respectively, were recognized in net realized investment gains. In addition, unrealized gains (losses) from other changes in total OTTI of $(2) million, $4 million and $5 million for the years ended December 31, 2015, 2014 and 2013, respectively, were recognized in other comprehensive income (loss) as part of changes in net unrealized gains on investment securities having credit losses recognized in the consolidated statement of income.