Equity (Common Stock - Narrative) (Details) - USD ($) $ in Millions	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014
Equity, Class of Treasury Stock [Line Items]
Treasury Stock, Shares, Acquired	22,475,816	8,168,318
Treasury Stock, Value, Acquired, Cost Method	$ 1,107	$ 443
Stock Repurchase Program, Remaining Authorized Repurchase Amount	893
Stock Repurchase Program, Authorized Amount	1,000
Board Increase Of Repurchase Program [Member]
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Authorized Amount	$ 739