Condensed Financial Information of Parent Company - Statements Of Cash Flows (Detail) (USD $) In Millions, unless otherwise specified	12 Months Ended
	Dec. 31, 2013	Dec. 31, 2012	Dec. 31, 2011
Cash Flows from Operating Activities
Net Income	$ 2,345	$ 1,545	$ 1,678
Adjustments to Reconcile Net Income to Net Cash Used in Operating Activities
Realized Investment Losses (Gains), Net	(402)	(193)	(288)
Other, Net	(20)	84	(27)
NET CASH PROVIDED BY OPERATING ACTIVITIES	1,731	2,299	1,878
Cash Flows from Investing Activities
Proceeds from Fixed Maturities Sales	2,449	2,271	1,730
Maturities, Calls and Redemptions	4,909	4,290	3,540
Proceeds from Sales of Equity Securities	545	160	167
Purchases of Fixed Maturities	(8,275)	(7,247)	(5,014)
Investments in Other Invested Assets, Net	498	293	285
Decrease (Increase) in Short Term Investments, Net	383	(629)	11
Other, Net	(6)
NET CASH PROVIDED BY (USED IN) INVESTING ACTIVITIES	252	(972)	580
Cash Flows from Financing Activities
Repayment of Long Term Debt	(275)		(400)
Proceeds from Issuance of Common Stock Under Stock-Based Employee Compensation Plans	38	74	80
Repurchase of Shares	(1,288)	(959)	(1,707)
Dividends Paid to Shareholders	(450)	(438)	(450)
NET CASH USED IN FINANCING ACTIVITIES	(1,981)	(1,335)	(2,470)
Net Increase in Cash	2	(8)	(12)
Cash at Beginning of Year	50	58	70
CASH AT END OF YEAR	52	50	58
Parent Company [Member]
Cash Flows from Operating Activities
Net Income	2,345	1,545	1,678
Adjustments to Reconcile Net Income to Net Cash Used in Operating Activities
Equity in Net Income of Consolidated Subsidiaries	(2,485)	(1,787)	(1,912)
Realized Investment Losses (Gains), Net	(99)	6	(9)
Other, Net	21	57	(28)
NET CASH PROVIDED BY OPERATING ACTIVITIES	(218)	(179)	(271)
Cash Flows from Investing Activities
Proceeds from Fixed Maturities Sales	227	24	2
Maturities, Calls and Redemptions	150	673	456
Proceeds from Sales of Equity Securities	296		9
Purchases of Fixed Maturities	(198)	(1,046)	(257)
Investments in Other Invested Assets, Net	22
Decrease (Increase) in Short Term Investments, Net	85	89	(219)
Dividends Received from Consolidated Insurance Subsidiaries	1,564	1,760	2,700
Distributions Received from Consolidated Non-Insurance Subsidiaries	1	1	1
Other, Net	46	1	56
NET CASH PROVIDED BY (USED IN) INVESTING ACTIVITIES	2,193	1,502	2,748
Cash Flows from Financing Activities
Repayment of Long Term Debt	(275)		(400)
Proceeds from Issuance of Common Stock Under Stock-Based Employee Compensation Plans	38	74	80
Repurchase of Shares	(1,288)	(959)	(1,707)
Dividends Paid to Shareholders	(450)	(438)	(450)
NET CASH USED IN FINANCING ACTIVITIES	(1,975)	(1,323)	(2,477)
Net Increase in Cash
Cash at Beginning of Year
CASH AT END OF YEAR