Consolidated Statement of Cash Flows (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Cash flows from operating activities
Net income	$ 1,426	$ 3,216	$ 3,622
Adjustments to reconcile net income to net cash provided by operating activities:
Net realized investment gains	(55)	(264)	(17)
Depreciation and amortization	802	812	797
Deferred federal income tax expense	63	178	213
Amortization of deferred acquisition costs	3,876	3,802	3,813
Equity in (income) loss from other investments	(281)	(283)	126
Change in premiums receivable	(237)	(29)	364
Change in reinsurance recoverables	807	1,300	1,416
Change in deferred acquisition costs	(3,881)	(3,826)	(3,797)
Change in claims and claim adjustment expense reserves	(152)	(1,968)	(1,596)
Change in unearned premium reserves	188	63	(96)
Other operating activities	(387)	53	(614)
Net cash provided by operating activities	2,169	3,054	4,231
Cash flows from investing activities
Proceeds from maturities of fixed maturities	7,404	5,896	5,316
Proceeds from sales of investments, fixed maturities	1,161	3,713	2,805
Proceeds from sales of investments, equity securities	135	201	65
Proceeds from sales of investments, real estate	1	10
Proceeds from sales of investments, other investments	594	717	511
Purchases of investments, fixed maturities	(8,704)	(6,785)	(9,647)
Purchases of investments, equity securities	(131)	(61)	(24)
Purchases of investments, real estate	(66)	(21)	(15)
Purchases of investments, other investments	(889)	(514)	(349)
Net sales (purchases) of short-term securities	2,018	(699)	370
Securities transactions in course of settlement		(30)	395
Other investing activities	(371)	(318)	(326)
Net cash provided by (used in) investing activities	1,152	2,109	(899)
Cash flows from financing activities
Payment of debt	(8)	(1,160)	(143)
Issuance of debt		1,234	494
Dividends paid to shareholders	(665)	(673)	(693)
Issuance of common stock - employee share options	314	408	180
Treasury stock acquired - share repurchase authorization	(2,919)	(4,998)	(3,259)
Treasury stock acquired - net employee share-based compensation	(46)	(40)	(29)
Excess tax benefits from share-based payment arrangements	18	8	8
Net cash used in financing activities	(3,306)	(5,221)	(3,442)
Effect of exchange rate changes on cash	(1)	3	15
Net increase (decrease) in cash	14	(55)	(95)
Cash at beginning of year	200	255	350
Cash at end of year	214	200	255
Supplemental disclosure of cash flow information
Income taxes paid	218	784	876
Interest paid	$ 382	$ 397	$ 385