Consolidated Statement of Cash Flows - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2019	Dec. 31, 2018	Dec. 31, 2017
Cash flows from operating activities
Net income		$ 2,622	$ 2,523	$ 2,056
Adjustments to reconcile net income to net cash provided by operating activities:
Net realized investment gains	[1]	(113)	(114)	(216)
Depreciation and amortization		763	803	813
Deferred federal income tax expense (benefit)		(33)	(13)	337
Amortization of deferred acquisition costs		4,601	4,381	4,166
Equity in income from other investments		(251)	(365)	(397)
Premiums receivable		(384)	(393)	(394)
Reinsurance recoverables		157	(100)	16
Deferred acquisition costs		(4,747)	(4,488)	(4,257)
Claims and claim adjustment expense reserves		1,047	1,246	1,460
Unearned premium reserves		1,008	710	521
Other operating activities		535	190	43
Net cash provided by operating activities		5,205	4,380	4,148
Cash flows from investing activities
Proceeds from maturities of fixed maturities		6,845	7,086	8,750
Proceeds from sales of investments:
Fixed maturities		2,187	3,546	1,854
Equity securities		140	178
Equity securities				765
Real estate investments		0	74	23
Other investments		459	511	468
Purchases of investments:
Fixed maturities		(10,711)	(13,526)	(12,250)
Equity securities		(94)	(117)
Equity securities				(459)
Real estate investments		(107)	(74)	(59)
Other investments		(497)	(537)	(541)
Net sales (purchases) of short-term securities		(957)	908	(26)
Securities transactions in the course of settlement		158	(56)	(47)
Acquisitions, net of cash acquired		0	(4)	(439)
Other investing activities		(325)	(318)	(241)
Net cash used in investing activities		(2,902)	(2,329)	(2,202)
Cash flows from financing activities
Treasury stock acquired — share repurchase authorization		(1,500)	(1,270)	(1,378)
Treasury stock acquired — net employee share-based compensation		(48)	(51)	(62)
Dividends paid to shareholders		(844)	(814)	(785)
Payment of debt		(500)	(600)	(657)
Issuance of debt		492	591	789
Issuance of common stock -- employee share options		213	132	173
Net cash used in financing activities		(2,187)	(2,012)	(1,920)
Effect of exchange rate changes on cash		5	(10)	11
Net increase in cash		121	29	37
Cash at beginning of year		373	344	307
Cash at end of year		494	373	344
Supplemental disclosure of cash flow information
Income taxes paid		428	408	514
Interest paid		$ 338	$ 347	$ 367

[1] Total other-than-temporary impairment (OTTI) losses were $(3) million, $(1) million and $(13) million for the years ended December 31, 2019, 2018 and 2017, respectively.  Of total OTTI, credit losses of $(4) million, $(1) million and $(14) million for the years ended December 31, 2019, 2018 and 2017, respectively, were recognized in net realized investment gains.  In addition, unrealized gains (losses) from other changes in total OTTI of $1 million, $0 million and $1 million for the years ended December 31, 2019, 2018 and 2017, 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.