Consolidated Statements 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	$ 4,847	$ 2,160	$ 3,554
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and other non-cash items	647	511	483
Realized capital gains and losses	(1,885)	877	(445)
Pension and other postretirement remeasurement gains and losses	114	468	(217)
Gain on disposition of operations	(6)	(6)	(20)
Interest credited to contractholder funds	640	654	690
Impairment of goodwill and purchased intangibles	106	0	125
Changes in:
Policy benefits and other insurance reserves	(508)	469	302
Unearned premiums	801	915	463
Deferred policy acquisition costs	(85)	(296)	(214)
Premium installment receivables, net	(299)	(396)	(131)
Reinsurance recoverables, net	320	(656)	(211)
Income taxes	487	(380)	(52)
Other operating assets and liabilities	(50)	855	(13)
Net cash provided by operating activities	5,129	5,175	4,314
Proceeds from sales
Fixed income securities	29,849	33,183	25,341
Equity securities	5,277	6,859	6,504
Limited partnership interests	756	764	1,125
Other investments	303	533	274
Investment collections
Fixed income securities	2,570	3,466	4,194
Mortgage loans	695	529	600
Other investments	254	488	642
Investment purchases
Fixed income securities	(31,317)	(36,960)	(31,145)
Equity securities	(7,176)	(5,936)	(6,585)
Limited partnership interests	(1,332)	(1,679)	(1,440)
Mortgage loans	(844)	(664)	(646)
Other investments	(666)	(864)	(999)
Change in short-term investments, net	(767)	(505)	2,610
Change in other investments, net	42	(98)	(30)
Purchases of property and equipment, net	(433)	(277)	(299)
Acquisition of operations	(18)	(558)	(1,356)
Net cash used in investing activities	(2,807)	(1,719)	(1,210)
Cash flows from financing activities
Proceeds from issuance of long-term debt	491	498	0
Redemption and repayment of long-term debt	(317)	(400)	0
Proceeds from issuance of preferred stock	1,414	557	0
Redemption of preferred stock	(1,132)	(385)	0
Contractholder fund deposits	996	1,010	1,025
Contractholder fund withdrawals	(1,662)	(1,967)	(1,890)
Dividends paid on common stock	(653)	(614)	(525)
Dividends paid on preferred stock	(134)	(134)	(116)
Treasury stock purchases	(1,735)	(2,303)	(1,495)
Shares reissued under equity incentive plans, net	120	73	135
Other	129	91	(57)
Net cash used in financing activities	(2,483)	(3,574)	(2,923)
Net (decrease) increase in cash	(161)	(118)	181
Cash at beginning of year	499	617	436
Cash at end of year	$ 338	$ 499	$ 617