Quarterly report pursuant to Section 13 or 15(d)

Derivatives - Gains and Losses on Derivatives Designated as Fair Value Hedges (Details)

v3.8.0.1
Derivatives - Gains and Losses on Derivatives Designated as Fair Value Hedges (Details) - USD ($)
$ in Millions
 3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Effect of Fair Value Hedges on Results of Operations [Abstract]    
Derivative $ (2,014) $ (610)
Hedged Item 1,920 396
Hedge Ineffectiveness   (214)
Interest rate risk on long-term debt | Interest expense    
Effect of Fair Value Hedges on Results of Operations [Abstract]    
Derivative (2,305) (750)
Hedged Item 2,236 566
Hedge Ineffectiveness   (184)
Gain (loss) on derivatives (64)  
Interest rate risk on long-term debt | Other income    
Effect of Fair Value Hedges on Results of Operations [Abstract]    
Gain (loss) on derivatives 433  
Interest rate and foreign currency risk on long-term debt    
Effect of Fair Value Hedges on Results of Operations [Abstract]    
Hedge ineffectiveness and amounts excluded from effectiveness testing (47)  
Interest rate and foreign currency risk on long-term debt | Interest expense    
Effect of Fair Value Hedges on Results of Operations [Abstract]    
Derivative 322 123
Hedged Item (346) (133)
Hedge Ineffectiveness   (10)
Gain (loss) on derivatives   (157)
Interest rate and foreign currency risk on long-term debt | Other income    
Effect of Fair Value Hedges on Results of Operations [Abstract]    
Gain (loss) on derivatives   280
Interest rate risk on AFS securities | Interest income    
Effect of Fair Value Hedges on Results of Operations [Abstract]    
Derivative (31) 17
Hedged Item $ 30 (37)
Hedge Ineffectiveness   $ (20)