Assumed Life Reinsurance Programs Involving Minimum Benefit Guarantees Under Annuity Contracts (Schedule Of Guaranteed Minimum Benefits Income And Expense) (Detail) (USD $) In Millions, unless otherwise specified	3 Months Ended		6 Months Ended
	Jun. 30, 2013	Jun. 30, 2012	Jun. 30, 2013	Jun. 30, 2012
Guaranteed Minimum Benefits [Line Items]
Net premiums earned	$ 4,067	$ 3,783	$ 7,640	$ 7,164
Policy benefits and other reserve adjustments	110	102	241	249
Net realized gains (losses)	104	(394)	310	(134)
Guaranteed Minimum Death Benefit [Member]
Guaranteed Minimum Benefits [Line Items]
Net premiums earned	20	21	40	44
Policy benefits and other reserve adjustments	25	12	44	39
Guaranteed Minimum Income Benefit [Member]
Guaranteed Minimum Benefits [Line Items]
Net premiums earned	37	40	76	81
Policy benefits and other reserve adjustments	2	16	11	23
Net realized gains (losses)	101	(494)	470	(34)
(Loss) gain recognized in income	136	(470)	535	24
Net cash received	31	38	63	79
Net (increase) decrease in liability	$ 105	$ (508)	$ 472	$ (55)