Equity Equity (Stock Repurchases) (Details) - USD ($) $ / shares in Units, $ in Millions	12 Months Ended			102 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2018
Equity, Class of Treasury Stock [Line Items]
Stock Repurchase Program, Remaining Authorized Repurchase Amount	$ 264			$ 264
Treasury Stock, Shares	154,905,595	155,924,785		154,905,595
Acquisition of treasury stock (shares)	0			154,300,000
Payments for Repurchase of Common Stock	$ 0	$ 0	$ 79
Treasury Stock Acquired, Average Cost Per Share				$ 12.12
Treasury Stock, Value, Acquired, Cost Method				$ 1,900