Condensed Consolidated Statements of Cash Flows - USD ($) $ in Millions	3 Months Ended
	Mar. 31, 2018	Mar. 31, 2017
Cash flows from operating activities
Net income	$ 975	$ 695
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation, amortization and other non-cash items	122	119
Realized capital gains and losses	134	(134)
Gain on disposition of operations	(1)	(2)
Interest credited to contractholder funds	161	173
Changes in:
Policy benefits and other insurance reserves	(364)	183
Unearned premiums	(204)	(248)
Deferred policy acquisition costs	10	14
Premium installment receivables, net	(58)	(19)
Reinsurance recoverables, net	(12)	11
Income taxes	181	284
Other operating assets and liabilities	(318)	(219)
Net cash provided by operating activities	626	857
Proceeds from sales
Fixed income securities	10,619	7,083
Equity securities	1,138	2,601
Limited partnership interests	53	210
Other investments	76	24
Investment collections
Fixed income securities	583	1,029
Mortgage loans	46	223
Other investments	122	174
Investment purchases
Fixed income securities	(9,789)	(8,800)
Equity securities	(1,535)	(2,383)
Limited partnership interests	(415)	(268)
Mortgage loans	(192)	(86)
Other investments	(330)	(219)
Change in short-term investments, net	(1,533)	1,572
Change in other investments, net	(27)	(10)
Purchases of property and equipment, net	(62)	(74)
Acquisition of operations	(5)	(1,356)
Net cash used in investing activities	(1,251)	(280)
Cash flows from financing activities
Proceeds from issuance of long-term debt	498	0
Proceeds from issuance of preferred stock	558	0
Contractholder fund deposits	253	257
Contractholder fund withdrawals	(492)	(483)
Dividends paid on common stock	(132)	(122)
Dividends paid on preferred stock	(29)	(29)
Treasury stock purchases	(270)	(264)
Shares reissued under equity incentive plans, net	10	67
Other	62	3
Net cash provided by (used in) financing activities	458	(571)
Net (decrease) increase in cash	(167)	6
Cash at beginning of period	617	436
Cash at end of period	$ 450	$ 442