Fair Value Measurements (Changes In Level 3 Assets And (Liabilities) Measured At Fair Value On A Recurring Basis) (Detail) - USD ($) $ in Millions	Dec. 31, 2021	Dec. 31, 2020
Fair Value, Assets Measured on Recurring Basis, Unobservable Input Reconciliation, Calculation [Roll Forward]
Net Assets Measured At Fair Value On A Recurring Basis	$ 3,600	$ 3,100
Net Assets Measured At Fair Value On A Recurring Basis Measured Using Unobservable Input And Classified As Level3	$ (4)	$ 7