Investments (Distribution By Contractual Maturity Of Available-For-Sale and Held-To-Maturity Investments) (Detail) - Fixed Maturities [Member] $ in Millions	Jun. 30, 2019 USD ($)
Available For Sale Securities [Abstract]
Due in one year or less	$ 726
Due after one year through five years	705
Due after five years through ten years	448
Due after ten years	744
Mortgage-Backed and Asset-Backed	703
Total Available-For-Sale, amortized cost	3,326
Due in one year or less	749
Due after one year through five years	764
Due after five years through ten years	431
Due after ten years	815
Mortgage-Backed and Asset-Backed	700
Total Available-For-Sale, fair value	3,459
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	967
Mortgage-Backed and Asset-Backed	0
Held-To-Maturity Securities Fair Value	$ 967