Quarterly report pursuant to Section 13 or 15(d)

Derivatives - Derivatives Designated as Cash Flow and Net Investment Hedges (Details)

v3.8.0.1
Derivatives - Derivatives Designated as Cash Flow and Net Investment Hedges (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Cash flow hedges    
Derivative Instruments, Gain (Loss) [Line Items]    
Gains (Losses) Recognized in Accumulated OCI on Derivatives $ (424) $ (9)
Gains (Losses) in Income Reclassified from Accumulated OCI (23) (70)
Interest rate risk on variable-rate assets (1) | Cash flow hedges    
Derivative Instruments, Gain (Loss) [Line Items]    
Gains (Losses) Recognized in Accumulated OCI on Derivatives (428) (37)
Gains (Losses) in Income Reclassified from Accumulated OCI (50) (112)
Price risk on restricted stock awards | Cash flow hedges    
Derivative Instruments, Gain (Loss) [Line Items]    
Gains (Losses) Recognized in Accumulated OCI on Derivatives 4 28
Gains (Losses) in Income Reclassified from Accumulated OCI 27 42
Foreign exchange risk | Net investment hedges    
Derivative Instruments, Gain (Loss) [Line Items]    
Gains (Losses) Recognized in Accumulated OCI on Derivatives (244) (389)
Gains (Losses) in Income Reclassified from Accumulated OCI (1) (130)
Hedge ineffectiveness and amounts excluded from effectiveness testing $ 4 $ (15)