Condensed Financial Information of Parent Company - Balance Sheets (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Assets
Short Term Investments	$ 2,114	$ 2,528
Taxable Fixed Maturities (cost $1,095 and $1,273)	37,091	38,076
Equity Securities (cost $ - and $176)	1,810	1,663
Other Invested Assets	1,598	1,954
TOTAL INVESTED ASSETS	42,613	44,221
Other Assets	1,205	1,353
TOTAL ASSETS	50,433	52,184	50,445
Liabilities
Long Term Debt	3,300	3,575
Dividend Payable to Shareholders	110	108
Accrued Expenses and Other Liabilities	1,357	2,188
TOTAL LIABILITIES	34,336	36,357
Shareholders' Equity
Preferred Stock - Authorized 8,000,000 Shares; $1 Par Value; Issued - None
Common Stock - Authorized 1,200,000,000 Shares; $1 Par Value; Issued 371,980,460 Shares	372	372
Paid-In Surplus	171	178
Retained Earnings	21,902	20,009
Accumulated Other Comprehensive Income	1,035	1,431
Treasury Stock, at Cost - 123,673,969 and 110,217,445 Shares	(7,383)	(6,163)
TOTAL SHAREHOLDERS' EQUITY	16,097	15,827	15,301
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	50,433	52,184
Parent Company [Member]
Assets
Short Term Investments	856	941
Taxable Fixed Maturities (cost $1,095 and $1,273)	1,110	1,309
Equity Securities (cost $ - and $176)	2	215
Other Invested Assets		46
TOTAL INVESTED ASSETS	1,968	2,511
Investment in Consolidated Subsidiaries	17,455	16,900
Other Assets	165	190
TOTAL ASSETS	19,588	19,601
Liabilities
Long Term Debt	3,300	3,575
Dividend Payable to Shareholders	110	108
Accrued Expenses and Other Liabilities	81	91
TOTAL LIABILITIES	3,491	3,774
Shareholders' Equity
Preferred Stock - Authorized 8,000,000 Shares; $1 Par Value; Issued - None
Common Stock - Authorized 1,200,000,000 Shares; $1 Par Value; Issued 371,980,460 Shares	372	372
Paid-In Surplus	171	178
Retained Earnings	21,902	20,009
Accumulated Other Comprehensive Income	1,035	1,431
Treasury Stock, at Cost - 123,673,969 and 110,217,445 Shares	(7,383)	(6,163)
TOTAL SHAREHOLDERS' EQUITY	16,097	15,827
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY	$ 19,588	$ 19,601