Quarterly report pursuant to Section 13 or 15(d)

Securities - Narrative (Details)

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Securities - Narrative (Details) - USD ($)
$ in Millions
3 Months Ended
Mar. 31, 2018
Mar. 31, 2017
Dec. 31, 2017
Schedule of Available-for-sale Securities [Line Items]      
Fair Value $ 290,360   $ 302,631
Equity securities, fair value 988    
Equity securities, cost 247    
Debt securities      
Schedule of Available-for-sale Securities [Line Items]      
Shareholders’ equity (5,500)    
Accumulated other comprehensive income tax expense (benefit) (1,800)    
Nonperforming Financing Receivable      
Schedule of Available-for-sale Securities [Line Items]      
Fair Value 128   $ 99
Other income      
Schedule of Available-for-sale Securities [Line Items]      
Unrealized mark-to-market net gains (losses) 41 $ 117  
Realized net gains (losses) $ (6) $ (103)