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		9 Months Ended
	Sep. 30, 2013	Sep. 30, 2012	Sep. 30, 2013	Sep. 30, 2012
Guaranteed Minimum Benefits [Line Items]
Net premiums earned	$ 4,610	$ 4,665	$ 12,250	$ 11,829
Policy benefits and other reserve adjustments	138	130	379	379
Net realized gains (losses)	40	(60)	350	(194)
Guaranteed Minimum Death Benefit [Member]
Guaranteed Minimum Benefits [Line Items]
Net premiums earned	19	20	59	64
Policy benefits and other reserve adjustments	14	22	58	61
Guaranteed Minimum Income Benefit [Member]
Guaranteed Minimum Benefits [Line Items]
Net premiums earned	36	40	112	121
Policy benefits and other reserve adjustments	9	7	20	30
Net realized gains (losses)	138	75	608	41
Gain recognized in income	165	108	700	132
Net cash received	31	35	94	114
Net decrease in liability	$ 134	$ 73	$ 606	$ 18