Investments (Distribution By Contractual Maturity Of Available-For-Sale and Held-To-Maturity Investments) (Detail) - Fixed Maturities [Member] $ in Millions	Sep. 30, 2021 USD ($)
Available For Sale Securities [Abstract]
Due in one year or less	$ 462
Due after one year through five years	308
Due after five years through ten years	321
Due after ten years	691
Mortgage-Backed and Asset-Backed	497
Total Available-For-Sale, amortized cost	2,279
Due in one year or less	462
Due after one year through five years	323
Due after five years through ten years	336
Due after ten years	773
Mortgage-Backed and Asset-Backed	510
Total Available-For-Sale, fair value	$ 2,404