XML 151 R77.htm IDEA: XBRL DOCUMENT v3.8.0.1
Investments in Securities Available-for-sale Securities 1 (Details) - USD ($)
$ in Millions
12 Months Ended
Dec. 31, 2017
Dec. 31, 2016
Dec. 31, 2015
Investments, Debt and Equity Securities [Abstract]      
Gross realized gains $ 487 $ 1,043 $ 1,066
Gross realized losses 1 17 70
Total proceeds (excludes initial sale of securities from new portfolio securitizations) $ 1,780 $ 10,993 $ 8,023