Related Party Transactions Transactions with Significant Shareholders (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions		12 Months Ended		66 Months Ended
	May. 18, 2015	Dec. 31, 2015	Dec. 31, 2013	Dec. 31, 2015
Related Party Transaction [Line Items]
Treasury Stock Acquired, Average Cost Per Share				$ 12.31
Treasury Stock, Shares, Acquired		39.7		145.6
Treasury Stock, Value, Acquired, Cost Method		$ 0	$ 0	$ 1,800
share repurchase program CIC buyback [Domain]
Related Party Transaction [Line Items]
Treasury Stock Acquired, Average Cost Per Share	$ 13.07
Treasury Stock, Shares, Acquired	20.0
Treasury Stock, Value, Acquired, Cost Method	$ 261
share repurchase program CIC buyback [Domain] | China investment Corporation (CIC) [Member]
Related Party Transaction [Line Items]
Treasury Stock Acquired, Average Cost Per Share	$ 13.07
Treasury Stock, Shares, Acquired	20.0
Treasury Stock, Value, Acquired, Cost Method	$ 261