Consolidated Statements of Cash Flows - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Cash Flows from Operating Activities
Net Income	$ 1,470	$ 1,542
Adjustments to Reconcile Net Income to Net Cash Provided by Operating Activities
Increase in Unpaid Losses and Loss Expenses, Net	176	151
Increase in Unearned Premiums, Net	182	242
Change in Income Tax Payable or Recoverable	(45)	163
Deferred Income Tax	107	66
Amortization of Premiums and Discounts on Fixed Maturities	173	143
Depreciation	39	41
Realized Investment Gains, Net	(113)	(351)
Other, Net	(32)	(78)
Net Cash Provided by Operating Activities	1,957	1,919
Cash Flows from Investing Activities
Proceeds from Fixed Maturities - Sales	3,197	3,243
Proceeds from Fixed Maturities - Maturities, Calls and Redemptions	3,207	3,162
Proceeds from Sales of Equity Securities	94	199
Purchases of Fixed Maturities	(5,683)	(7,517)
Purchases of Equity Securities	(48)	(109)
Investments in Other Invested Assets, Net	74	189
Decrease (Increase) in Short Term Investments, Net	(1,757)	56
Change in Receivable or Payable from Security Transactions Not Settled, Net	14	457
Purchases of Property and Equipment, Net	(54)	(44)
Net Cash Used in Investing Activities	(956)	(364)
Cash Flows from Financing Activities
Decrease in Funds Held Under Deposit Contracts	(3)	(2)
Proceeds from Issuance of Common Stock Under Stock-Based Employee Compensation Plans	13	18
Repurchase of Shares	(624)	(1,210)
Dividends Paid to Shareholders	(381)	(356)
Net Cash Used in Financing Activities	(995)	(1,550)
Net Increase in Cash	6	5
Cash at Beginning of Year	47	52
Cash at End of Period	$ 53	$ 57