Investments (Distribution By Contractual Maturity Of Available-For-Sale and Held-To-Maturity Investments) (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2013	Dec. 31, 2012
Available For Sale Securities [Abstract]
Total Available-For-Sale, Amortized Cost	$ 6,824	$ 6,122
Total available-for-sale, fair value	6,692	6,221
Held To Maturity Securities [Abstract]
Total Held-To-Maturity, Amortized Cost	2,801	2,829
Total held-to- maturity, fair value	2,651	2,674
Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Due in one year or less	521
Due after one year through five years	992
Due after five years through ten years	1,021
Due after ten years	1,691
Mortgage-Backed and Asset-Backed	1,672
Total Available-For-Sale, Amortized Cost	5,897	4,883
Due in one year or less	521
Due after one year through five years	1,006
Due after five years through ten years	1,006
Due after ten years	1,639
Mortgage-Backed and Asset-Backed	1,592
Total available-for-sale, fair value	5,764	4,993
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	2,801
Mortgage-Backed and Asset-Backed	0
Total Held-To-Maturity, Amortized Cost	2,801
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	2,651
Mortgage-Backed and Asset-Backed	0
Total held-to- maturity, fair value	$ 2,651