Equity (Common Stock - Narrative) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2017	Sep. 30, 2016
Equity [Abstract]
Treasury Stock, Shares, Acquired	44,737,625	1,445,864
Treasury Stock, Value, Acquired, Cost Method	$ 2,305	$ 70
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 383