Quarterly report pursuant to Section 13 or 15(d)

Amount Recorded in Income Statements for Foreign Currency Forward Contracts Not Designated as Hedges (Detail)

v3.8.0.1
Amount Recorded in Income Statements for Foreign Currency Forward Contracts Not Designated as Hedges (Detail) - Not Designated as Hedging Instrument - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Derivative Instruments, Gain (Loss) [Line Items]    
Amount of Gain (Loss) Recognized in Income $ 22 $ 30
Interest rate contracts | Interest Expense    
Derivative Instruments, Gain (Loss) [Line Items]    
Amount of Gain (Loss) Recognized in Income (2) (2)
Foreign exchange contracts | Investment income and other    
Derivative Instruments, Gain (Loss) [Line Items]    
Amount of Gain (Loss) Recognized in Income 8 6
Investment market price contracts | Investment income and other    
Derivative Instruments, Gain (Loss) [Line Items]    
Amount of Gain (Loss) Recognized in Income $ 16 $ 26