Investments (Distribution By Contractual Maturity Of Available-For-Sale and Held-To-Maturity Investments) (Detail) - USD ($) $ in Millions	Jun. 30, 2015	Dec. 31, 2014
Held To Maturity Securities [Abstract]
Total Held-To-Maturity, amortized cost	$ 2,724	$ 2,757
Total Held-To-Maturity, fair value	2,580	$ 2,632
Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Due in one year or less	809
Due after one year through five years	1,433
Due after five years through ten years	919
Due after ten years	1,464
Mortgage-Backed and Asset-Backed	1,583
Total Available-For-Sale, amortized cost	6,208
Due in one year or less	812
Due after one year through five years	1,453
Due after five years through ten years	937
Due after ten years	1,427
Mortgage-Backed and Asset-Backed	1,554
Total Available-For-Sale, fair value	6,183
Fixed Maturities [Member] | Variable Interest Entity Primary Beneficiary [Member]
Held To Maturity Securities [Abstract]
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	0
Due after ten years	2,724
Mortgage-Backed and Asset-Backed	0
Total Held-To-Maturity, amortized cost	2,724
Due in one year or less	0
Due after one year through five years	0
Due after five years through ten years	0
Due after ten years	2,580
Mortgage-Backed and Asset-Backed	0
Total Held-To-Maturity, fair value	$ 2,580