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
	Mar. 31, 2015	Mar. 31, 2014
Guaranteed Minimum Benefits [Line Items]
Document Fiscal Year Focus	2015
Net premiums earned	$ 3,927	$ 3,970
Policy benefits and other reserve adjustments	142	114
Net realized gains (losses)	(89)	(104)
Guaranteed Minimum Death Benefit [Member]
Guaranteed Minimum Benefits [Line Items]
Net premiums earned	16	19
Policy benefits and other reserve adjustments	9	15
Guaranteed Living Benefit [Member]
Guaranteed Minimum Benefits [Line Items]
Net premiums earned	32	36
Policy benefits and other reserve adjustments	12	9
Net realized gains (losses)	(45)	(50)
Loss recognized in Net income	(25)	(23)
Less: Net cash received	28	33
Net increase in liability	$ (53)	$ (56)