Equity (Common Stock - Narrative) (Details) - USD ($) $ in Millions	6 Months Ended
	Jun. 30, 2017	Jun. 30, 2016
Equity [Abstract]
Treasury Stock, Shares, Acquired	34,354,967	1,445,864
Treasury Stock, Value, Acquired, Cost Method	$ 1,810	$ 70
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 888