Investments (Distribution By Contractual Maturity Of Available-For-Sale and Held-To-Maturity Investments) (Detail) (USD $) In Millions, unless otherwise specified	Dec. 31, 2014	Dec. 31, 2013
Held To Maturity Securities [Abstract]
Total Held-To-Maturity, amortized cost	$ 2,757us-gaap_HeldToMaturitySecurities	$ 2,801us-gaap_HeldToMaturitySecurities
Total Held-To-Maturity, fair value	2,632	2,651
Fixed Maturities [Member]
Available For Sale Securities [Abstract]
Due in one year or less	806
Due after one year through five years	1,388
Due after five years through ten years	889
Due after ten years	1,459
Mortgage-Backed and Asset-Backed	1,533
Total Available-For-Sale, amortized cost	6,075
Due in one year or less	806
Due after one year through five years	1,412
Due after five years through ten years	914
Due after ten years	1,491
Mortgage-Backed and Asset-Backed	1,513
Total Available-For-Sale, fair value	6,136
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	2,757
Mortgage-Backed and Asset-Backed	0
Total Held-To-Maturity, amortized cost	2,757
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	2,632
Mortgage-Backed and Asset-Backed	0
Total Held-To-Maturity, fair value	$ 2,632

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Amount of available-for-sale debt securities at cost, net of adjustments, which include, but are not limited to, accretion, amortization, collection of cash, previous other-than-temporary impairments (OTTI) recognized in earnings (less any cumulative-effect adjustments, as defined) and fair value hedge accounting adjustments.