Consolidated Statement of Cash Flows (Unaudited) - USD ($) $ in Millions		3 Months Ended
		Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities
Net income		$ 669	$ 617
Adjustments to reconcile net income to net cash provided by operating activities:
Net realized investment (gains) losses	[1]	11	(5)
Depreciation and amortization		212	211
Deferred federal income tax expense (benefit)		(56)	151
Amortization of deferred acquisition costs		1,061	1,003
Equity in income from other investments		(95)	(109)
Premiums receivable		(397)	(286)
Reinsurance recoverables		5	94
Deferred acquisition costs		(1,124)	(1,065)
Claims and claim adjustment expense reserves		180	334
Unearned premium reserves		518	475
Other operating activities		(430)	(572)
Net cash provided by operating activities		554	848
Cash flows from investing activities
Proceeds from maturities of fixed maturities		1,950	2,218
Proceeds from sales of investments:
Fixed maturities		1,085	188
Equity securities		26
Equity securities			21
Real estate investments			11
Other investments		114	122
Purchases of investments:
Fixed maturities		(3,920)	(3,056)
Equity securities		(20)
Equity securities			(22)
Real estate investments		(33)	(16)
Other investments		(142)	(124)
Net sales of short-term securities		410	49
Securities transactions in course of settlement		202	157
Other investing activities		(53)	(63)
Net cash used in investing activities		(381)	(515)
Cash flows from financing activities
Treasury stock acquired — share repurchase authorization		(350)	(225)
Treasury stock acquired — net employee share-based compensation		(51)	(61)
Dividends paid to shareholders		(197)	(190)
Payment of debt		(100)
Issuance of debt		491
Issuance of common stock — employee share options		85	83
Net cash used in financing activities		(122)	(393)
Effect of exchange rate changes on cash		2	2
Net increase (decrease) in cash		53	(58)
Cash at beginning of year		344	307
Cash at end of period		397	249
Supplemental disclosure of cash flow information
Income taxes paid		56	2
Interest paid		$ 39	$ 43

[1] Total other-than-temporary impairment (OTTI) gains (losses) were $0 and $(1) million for the three months ended March 31, 2018 and 2017, respectively. Of total OTTI, credit losses of $0 and $(2) million for the three months ended March 31, 2018 and 2017, respectively, were recognized in net realized investment gains (losses). In addition, unrealized gains from other changes in total OTTI of $0 and $1 million for the three months ended March 31, 2018 and 2017, 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.