Condensed Financial Information of Parent Company (Details) (USD $) In Millions, unless otherwise specified	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Assets
Short Term Investments	$ 1,893	$ 1,905
Fixed maturities	37,184	36,519
Equity securities	1,512	1,550
Other Invested Assets	2,180	2,239
TOTAL INVESTED ASSETS	42,769	42,213
Other Assets	1,281	1,152
TOTAL ASSETS	50,865	50,249	50,449
Liabilities
Long Term Debt	3,575	3,975
Dividend Payable to Shareholders	107	112
Accrued Expenses and Other Liabilities	2,070	1,725
TOTAL LIABILITIES	35,291	34,719
Shareholders' Equity
Preferred Stock - Authorized 8,000,000 Shares; $1 Par Value; Issued - None	0	0
Common Stock - Authorized 1,200,000,000 Shares; $1 Par Value; Issued 371,980,460 Shares	372	372
Paid-In Surplus	190	208
Retained Earnings	19,176	17,943
Accumulated Other Comprehensive Income	1,195	790
Treasury Stock, at Cost - 99,519,509 and 74,707,547 Shares	(5,359)	(3,783)
TOTAL SHAREHOLDERS' EQUITY	15,574	15,530	15,634
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	50,865	50,249
Parent Company [Member]
Assets
Short Term Investments	1,030	811
Fixed maturities	962	1,181
Equity securities	179	171
Other Invested Assets	27	23
TOTAL INVESTED ASSETS	2,198	2,186
Investment in Consolidated Subsidiaries	16,951	17,337
Other Assets	188	162
TOTAL ASSETS	19,337	19,685
Liabilities
Long Term Debt	3,575	3,975
Dividend Payable to Shareholders	107	112
Accrued Expenses and Other Liabilities	81	68
TOTAL LIABILITIES	3,763	4,155
Shareholders' Equity
Preferred Stock - Authorized 8,000,000 Shares; $1 Par Value; Issued - None	0	0
Common Stock - Authorized 1,200,000,000 Shares; $1 Par Value; Issued 371,980,460 Shares	372	372
Paid-In Surplus	190	208
Retained Earnings	19,176	17,943
Accumulated Other Comprehensive Income	1,195	790
Treasury Stock, at Cost - 99,519,509 and 74,707,547 Shares	(5,359)	(3,783)
TOTAL SHAREHOLDERS' EQUITY	15,574	15,530
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	$ 19,337	$ 19,685