Basis of Presentation Basis of Presentation (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016	Sep. 30, 2017	Sep. 30, 2016	Dec. 31, 2016	Dec. 31, 2015
Defined Benefit Plan, Effect of Plan Amendment on Net Periodic Benefit Cost	$ 18		$ 18
Plan Amendment, Effect on AOCI	182		182
Plan amendment - effect on funded status	164		164
Cash Segregated under Commodity Exchange Act Regulation	1,200		1,200
Cash Provided by (Used in) Financing Activities, Discontinued Operations			2,155	$ 1,296
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, at Carrying Value	1,794	$ 1,727	1,794	1,727	$ 1,561	$ 1,796
Cost Of Products Sold [Member]
Floor Brokerage, Exchange and Clearance Fees	$ 17	15	$ 49	50
Selling, General and Administrative Expenses [Member]
Floor Brokerage, Exchange and Clearance Fees		(15)		(50)
Restatement Adjustment [Member]
Cash Provided by (Used in) Financing Activities, Discontinued Operations				145
Cash, Cash Equivalents, Restricted Cash, and Restricted Cash Equivalents, at Carrying Value		$ 938		$ 938