Quarterly report pursuant to Section 13 or 15(d)

Investments (Details)

v3.7.0.1
Investments (Details) - USD ($)
$ in Millions
Jun. 30, 2017
Dec. 31, 2016
Schedule of Trading Securities and Other Trading Assets [Line Items]    
Total trading securities $ 415 $ 384
Trading Securities    
Trading Securities Unrealized Holding Gains (Losses) 109 39
Marketable Securities 309 282
Other Assets $ 106 $ 102