Consolidated Statements of Cash Flows (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2012	Dec. 31, 2011	Dec. 31, 2010
Cash Flows from Operating Activities
Net Income	$ 1,624	$ 1,261	$ 1,283
Adjustments to reconcile net income to net cash provided by operating activities:
Depreciation and amortization	560	345	292
Realized investment (gains) losses	(44)	(62)	(75)
Deferred income taxes	134	217	188
Gains on sale of businesses (excluding discontinued operations)	(18)	(25)	(13)
(Income) from discontinued operations	0	0	0
Net changes in assets and liabilities, net of non-operating effects:
Premiums, accounts and notes receivable	(71)	(50)	62
Reinsurance recoverables	62	19	37
Deferred policy acquisition costs	(159)	(129)	(94)
Other assets	31	(307)	3
Insurance liabilities	245	154	325
Accounts payable, accrued expenses and other liabilities	(132)	344	(272)
Current income taxes	29	(246)	2
Proceeds from sales of mortgage loans held for sale	61	0	0
Other, net	28	(30)	5
Net cash provided by operating activities	2,350	1,491	1,743
Proceeds from investments sold:
Fixed maturities	583	830	822
Equity securities	8	46	4
Commercial mortgage loans	380	253	63
Other (primarily short-term and other long-term investments)	831	1,915	1,102
Investment maturities and repayments:
Fixed maturities	1,507	1,265	1,084
Commercial mortgage loans	342	385	70
Investments purchased:
Fixed maturities	(2,326)	(2,877)	(2,587)
Equity securities	(8)	(20)	(12)
Commercial mortgage loans	(364)	(487)	(239)
Other (primarily short-term and other long-term investments)	(821)	(2,056)	(810)
Property and equipment purchases	(408)	(422)	(300)
Acquisitions and dispositions, net of cash acquired	(3,581)	(102)	(539)
Net cash used in investing activities	(3,857)	(1,270)	(1,342)
Cash Flows from Financing Activities
Deposits and interest credited to contractholder deposit funds	1,337	1,323	1,295
Withdrawals and benefit payments from contractholder deposit funds	(1,264)	(1,178)	(1,205)
Change in cash overdraft position	25	(1)	59
Net change in short-term debt	98	0	0
Net proceeds on issuance of long-term debt	0	2,676	543
Repayment of long-term debt	(326)	(451)	(270)
Repurchase of common stock	(208)	(225)	(201)
Issuance of common stock	121	734	64
Common dividends paid	(11)	(11)	(11)
Net cash provided by financing activities	(228)	2,867	274
Effect of foreign currency rate changes on cash and cash equivalents	23	(3)	6
Net increase (decrease) in cash and cash equivalents	(1,712)	3,085	681
Cash and cash equivalents, beginning of year	4,690	1,605	924
Cash and cash equivalents, end of year	2,978	4,690	1,605
Supplemental Disclosure of Cash Information:
Income taxes paid, net of refunds	655	633	326
Interest paid	$ 248	$ 185	$ 180