Investments (Distribution By Contractual Maturity Of Available-For-Sale and Held-To-Maturity Investments) (Detail) - USD ($) $ in Millions	Mar. 31, 2016	Dec. 31, 2015
Variable Interest Entity Primary Beneficiary [Member]
Held To Maturity Securities [Abstract]
Total Held-To-Maturity, amortized cost	$ 890	$ 2,689
Total Held-To-Maturity, fair value	525	$ 2,401
Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Due in one year or less	609
Due after one year through five years	1,582
Due after five years through ten years	883
Due after ten years	1,481
Mortgage-Backed and Asset-Backed	1,458
Total Available-For-Sale, amortized cost	6,013
Due in one year or less	609
Due after one year through five years	1,609
Due after five years through ten years	929
Due after ten years	1,498
Mortgage-Backed and Asset-Backed	1,432
Total Available-For-Sale, fair value	6,077
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	890
Mortgage-Backed and Asset-Backed	0
Total Held-To-Maturity, amortized cost	890
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	525
Mortgage-Backed and Asset-Backed	0
Total Held-To-Maturity, fair value	$ 525