Consolidated Statement of Cash Flows - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Cash flows from operating activities
Net income		$ 2,523	$ 2,056	$ 3,014
Adjustments to reconcile net income to net cash provided by operating activities:
Net realized investment gains	[1]	(114)	(216)	(68)
Depreciation and amortization		803	813	826
Deferred federal income tax expense (benefit)		(13)	337	110
Amortization of deferred acquisition costs		4,381	4,166	3,985
Equity in income from other investments		(365)	(397)	(232)
Premiums receivable		(393)	(394)	(286)
Reinsurance recoverables		(100)	16	610
Deferred acquisition costs		(4,488)	(4,257)	(4,061)
Claims and claim adjustment expense reserves		1,246	1,460	(257)
Unearned premium reserves		710	521	372
Other operating activities		190	43	456
Net cash provided by operating activities		4,380	4,148	4,469
Cash flows from investing activities
Proceeds from maturities of fixed maturities		7,086	8,750	8,975
Proceeds from sales of investments:
Fixed maturities		3,546	1,854	1,417
Equity securities		178
Equity securities			765	92
Real estate investments		74	23	69
Other investments		511	468	566
Purchases of investments:
Fixed maturities		(13,526)	(12,250)	(11,609)
Equity securities		(117)
Equity securities			(459)	(51)
Real estate investments		(74)	(59)	(48)
Other investments		(537)	(541)	(580)
Net sales (purchases) of short-term securities		908	(26)	(199)
Securities transactions in the course of settlement		(56)	(47)	(21)
Acquisitions, net of cash acquired		(4)	(439)
Other investing activities		(318)	(241)	(338)
Net cash used in investing activities		(2,329)	(2,202)	(1,727)
Cash flows from financing activities
Treasury stock acquired — share repurchase authorization		(1,270)	(1,378)	(2,400)
Treasury stock acquired — net employee share-based compensation		(51)	(62)	(72)
Dividends paid to shareholders		(814)	(785)	(757)
Payment of debt		(600)	(657)	(400)
Issuance of debt		591	789	491
Issuance of common stock -- employee share options		132	173	332
Net cash used in financing activities		(2,012)	(1,920)	(2,806)
Effect of exchange rate changes on cash		(10)	11	(9)
Net increase (decrease) in cash		29	37	(73)
Cash at beginning of year		344	307	380
Cash at end of year		373	344	307
Supplemental disclosure of cash flow information
Income taxes paid		408	514	892
Interest paid		$ 347	$ 367	$ 358

[1] Total other-than-temporary impairment (OTTI) losses were $(1) million, $(13) million and $(40) million for the years ended December 31, 2018, 2017 and 2016, respectively. Of total OTTI, credit losses of $(1) million, $(14) million and $(29) million for the years ended December 31, 2018, 2017 and 2016, respectively, were recognized in net realized investment gains. In addition, unrealized gains (losses) from other changes in total OTTI of $0 million, $1 million and $(11) million for the years ended December 31, 2018, 2017 and 2016, respectively, were recognized in other comprehensive income (loss) as part of changes in net unrealized gains (losses) on investment securities having credit losses recognized in the consolidated statement of income.