Consolidated Balance Sheets - USD ($) $ in Millions	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Assets
Fixed maturities, available for sale, at fair value (amortized cost $61,316 and $59,650)	$ 62,694	$ 60,515
Equity securities, available for sale, at fair value (cost $440 and $504)	453	732
Real estate investments	932	928
Short-term securities	4,895	4,865
Other investments	3,528	3,448
Total investments	72,502	70,488
Cash	344	307	$ 380	$ 374
Investment income accrued	606	630
Premiums receivable	7,144	6,722
Reinsurance recoverables	8,309	8,287
Ceded unearned premiums	551	589
Deferred acquisition costs	2,025	1,923	1,849
Deferred taxes	70	465
Contractholder receivables	4,775	4,609
Goodwill	3,951	3,580
Other intangible assets	342	268
Other assets	2,864	2,377
Total assets	103,483	100,245
Liabilities
Claims and claim adjustment expense reserves	49,650	47,949	48,295
Unearned premium reserves	12,915	12,329	11,971
Contractholder payables	4,775	4,609
Payables for reinsurance premiums	274	273
Debt	6,571	6,437
Other liabilities	5,567	5,427
Total liabilities	79,752	77,024
Shareholders' equity
Common stock (1,750.0 shares authorized; 271.5 and 279.6 shares issued and 271.4 and 279.6 shares outstanding)	22,886	22,614
Retained earnings	33,462	32,196
Accumulated other comprehensive loss	(343)	(755)
Treasury stock, at cost (500.9 and 489.5 shares)	(32,274)	(30,834)
Total shareholders' equity	23,731	23,221	$ 23,598
Total liabilities and shareholders' equity	$ 103,483	$ 100,245