Quarterly report pursuant to Section 13 or 15(d)

Derivatives - Derivatives Designated as Fair Value Hedges (Details)

v3.8.0.1
Derivatives - Derivatives Designated as Fair Value Hedges (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2017
Sep. 30, 2016
Sep. 30, 2017
Sep. 30, 2016
Effect of Fair Value Hedges on Results of Operations [Abstract]        
Derivative $ 326 $ (501) $ 817 $ 3,395
Hedged Item (418) 314 (1,258) (3,943)
Hedge Ineffectiveness (92) (187) (441) (548)
Interest rate risk on long-term debt | Interest expense        
Effect of Fair Value Hedges on Results of Operations [Abstract]        
Derivative (273) (758) (751) 3,166
Hedged Item 169 580 313 (3,654)
Hedge Ineffectiveness (104) (178) (438) (488)
Interest rate and foreign currency risk on long-term debt | Interest expense        
Effect of Fair Value Hedges on Results of Operations [Abstract]        
Derivative 607 16 1,631 360
Hedged Item (593) (10) (1,603) (369)
Hedge Ineffectiveness 14 6 28 (9)
Interest rate risk on AFS securities | Interest income        
Effect of Fair Value Hedges on Results of Operations [Abstract]        
Derivative (8) 235 (71) (131)
Hedged Item 7 (250) 40 80
Hedge Ineffectiveness (1) (15) (31) (51)
Price risk on commodity inventory | Trading gain (loss)        
Effect of Fair Value Hedges on Results of Operations [Abstract]        
Derivative 0 6 8 0
Hedged Item (1) (6) (8) 0
Hedge Ineffectiveness $ (1) $ 0 $ 0 $ 0