Quarterly report pursuant to Section 13 or 15(d)

Securities - Narrative (Details)

v3.10.0.1
Securities - Narrative (Details) - USD ($)
$ in Millions
3 Months Ended 9 Months Ended
Sep. 30, 2018
Sep. 30, 2017
Sep. 30, 2018
Sep. 30, 2017
Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]          
Fair Value $ 239,048   $ 239,048   $ 302,631
Unrealized mark-to-market net gains (losses) (106) $ 124 (37) $ 323  
Realized net gains (losses) 114 $ (11) 123 $ (129)  
Other assets          
Schedule of Available-for-sale Securities [Line Items]          
Equity securities, fair value 947   947    
Equity securities, cost 252   252    
Time Deposits Placed and Other Short-term Investments          
Schedule of Available-for-sale Securities [Line Items]          
Equity securities, fair value 1,500   1,500    
Nonperforming Financing Receivable          
Schedule of Available-for-sale Securities [Line Items]          
Fair Value 71   71   $ 99
Debt securities          
Schedule of Available-for-sale Securities [Line Items]          
Shareholders’ equity (6,400)   (6,400)    
Accumulated other comprehensive income tax expense (benefit) $ (2,100)   $ (2,100)