Derivative Instruments And Hedging Activities - Gains (Losses) Recognized in AOCI and Reclassified from AOCI on Derivatives (Effective Portion) (Detail) - Accounting Standards Update 2018-02 - USD ($) $ in Millions	Dec. 31, 2019	Jan. 01, 2019
Derivative Instruments, Gain (Loss) [Line Items]
Effect of adoption adjustment reduction to retained earnings		$ 0
Retained Earnings
Derivative Instruments, Gain (Loss) [Line Items]
Effect of adoption adjustment reduction to retained earnings		20
Retained Earnings | Net Investment Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Effect of adoption adjustment reduction to retained earnings	$ 3
Accumulated Other Comprehensive Loss
Derivative Instruments, Gain (Loss) [Line Items]
Effect of adoption adjustment reduction to retained earnings		$ (20)
Accumulated Other Comprehensive Loss | Net Investment Hedging
Derivative Instruments, Gain (Loss) [Line Items]
Effect of adoption adjustment reduction to retained earnings	$ 3