Consolidated Statements 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	$ 1,678	$ 2,174	$ 2,183
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities
Increase in Unpaid Losses and Loss Expenses, Net	361	145	262
Increase (Decrease) in Unearned Premiums, Net	114	21	(254)
Decrease (Increase) in Premiums Receivable	(63)	3	100
Change in Income Tax Payable or Recoverable	(102)	178	(27)
Deferred Income Tax	25	136	86
Amortization of Premiums and Discounts on Fixed Maturities	147	154	168
Depreciation	58	63	69
Realized Investment Gains, Net	(288)	(426)	(23)
Other, Net	(52)	(117)	(147)
NET CASH PROVIDED BY (USED IN) OPERATING ACTIVITIES	1,878	2,331	2,417
Cash Flows from Investing Activities
Proceeds from Fixed Maturities - Sales	1,730	2,287	3,029
Proceeds from Fixed Maturities - Maturities, Calls and Redemptions	3,540	2,856	2,578
Proceeds from Sales of Equity Securities	167	129	394
Purchases of Fixed Maturities	(5,014)	(5,176)	(7,372)
Purchases of Equity Securities	(95)	(156)	(37)
Investments in Other Invested Assets, Net	285	173	(37)
Decrease (Increase) in Short Term Investments, Net	11	38	563
Increase (Decrease) in Net Payable from Security Transactions not Settled	8	(24)	72
Purchases of Property and Equipment, Net	(52)	(54)	(52)
Other, Net		(6)	6
NET CASH PROVIDED BY (USED IN) INVESTING ACTIVITIES	580	67	(856)
Cash Flows from Financing Activities
Repayment of Long Term Debt	(400)	0	0
Increase (Decrease) in Funds Held Under Deposit Contracts	7	22	(53)
Proceeds from Issuance of Common Stock Under Stock-Based Employee Compensation Plans	80	74	34
Repurchase of Shares	(1,707)	(2,003)	(1,060)
Dividends Paid to Shareholders	(450)	(472)	(487)
NET CASH USED IN FINANCING ACTIVITIES	(2,470)	(2,379)	(1,566)
Net Increase (Decrease) in Cash	(12)	19	(5)
Cash at Beginning of Year	70	51	56
CASH AT END OF YEAR	$ 58	$ 70	$ 51