Assumed Life Reinsurance Programs Involving Minimum Benefit Guarantees Under Annuity Contracts (Schedule Of Guaranteed Minimum Benefits Income And Expense) (Detail) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Guaranteed Minimum Benefits [Line Items]
Net premiums earned	$ 4,719	$ 4,754	$ 13,006	$ 13,056
Policy benefits and other reserve adjustments	89	125	384	383
Net realized gains (losses)	(397)	(120)	(360)	(297)
Guaranteed Minimum Death Benefit [Member]
Guaranteed Minimum Benefits [Line Items]
Net premiums earned	15	17	47	54
Policy benefits and other reserve adjustments	5	12	25	40
Guaranteed Living Benefit [Member]
Guaranteed Minimum Benefits [Line Items]
Net premiums earned	30	35	92	105
Policy benefits and other reserve adjustments	15	8	34	27
Net realized gains (losses)	(397)	(76)	(338)	(124)
Loss recognized in Net income	(382)	(49)	(280)	(46)
Less: Net cash received	20	31	74	93
Net increase in liability	$ (402)	$ (80)	$ (354)	$ (139)