Annual report pursuant to Section 13 and 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
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Cash flow hedges      
Derivative Instruments, Gain (Loss) [Line Items]      
Gains (Losses) Recognized in Accumulated OCI on Derivatives $ (50) $ (299) $ 55
Gains (Losses) in Income Reclassified from Accumulated OCI (179) (585) (883)
Interest rate risk on variable-rate portfolios | Cash flow hedges      
Derivative Instruments, Gain (Loss) [Line Items]      
Gains (Losses) Recognized in Accumulated OCI on Derivatives (109) (340) 95
Gains (Losses) in Income Reclassified from Accumulated OCI (327) (553) (974)
Price risk on restricted stock awards | Cash flow hedges      
Derivative Instruments, Gain (Loss) [Line Items]      
Gains (Losses) Recognized in Accumulated OCI on Derivatives 59 41 (40)
Gains (Losses) in Income Reclassified from Accumulated OCI 148 (32) 91
Foreign exchange risk | Net investment hedges      
Derivative Instruments, Gain (Loss) [Line Items]      
Gains (Losses) Recognized in Accumulated OCI on Derivatives (1,588) 1,636 3,010
Gains (Losses) in Income Reclassified from Accumulated OCI 1,782 3 153
Hedge Ineffectiveness and Amounts Excluded from Effectiveness Testing $ (120) $ (325) $ (298)