Quarterly report pursuant to Section 13 or 15(d)

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

v3.7.0.1
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 6 Months Ended
Jun. 30, 2017
Jun. 30, 2016
Jun. 30, 2017
Jun. 30, 2016
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of Gain (Loss) Recognized in Income $ (6) $ (42) $ 24 $ 70
Interest Rate Contract [Member] | Interest Expense [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of Gain (Loss) Recognized in Income (2) (2) (4) (4)
Foreign Exchange Contracts | Investment Income [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of Gain (Loss) Recognized in Income 14 (65) 20 (106)
Price Risk Derivative [Member] | Investment Income [Member]        
Derivative Instruments, Gain (Loss) [Line Items]        
Amount of Gain (Loss) Recognized in Income $ (18) $ 25 $ 8 $ 180