Subsequent Events (Details) - USD ($) $ / shares in Units, shares in Millions, $ in Millions					1 Months Ended	3 Months Ended		9 Months Ended		63 Months Ended	64 Months Ended
	Nov. 02, 2015	Oct. 08, 2015	Oct. 01, 2015	Sep. 24, 2015	Nov. 04, 2015	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Nov. 04, 2015
Subsequent Event [Line Items]
Common Stock, Dividends, Per Share, Declared						$ 0.10	$ 0.05	$ 0.20	$ 0.10
Treasury Stock, Shares, Acquired						8.4				137.9
Stock Repurchased During Period, Value						$ 101		$ 408	$ 140	$ 1,700
Treasury Stock Acquired, Average Cost Per Share										$ 12.44
Stock Repurchase Program, Remaining Authorized Repurchase Amount						$ 16		$ 16		$ 16
Solar Spain [Member]
Subsequent Event [Line Items]
Equity Method Investment, Net Sales Proceeds				$ 31
Subsequent Event [Member]
Subsequent Event [Line Items]
Common Stock, Dividends, Per Share, Declared		$ 0.10
Treasury Stock, Shares, Acquired					1.6						139.5
Stock Repurchased During Period, Value					$ 16						$ 1,700
Treasury Stock Acquired, Average Cost Per Share											$ 12.41
Stock repurchase program, additional authorized amount	$ 400
Stock Repurchase Program, Number of Shares Authorized to be Repurchased	$ 2,100
Stock Repurchase Program, Remaining Authorized Repurchase Amount					$ 400						$ 400
Silver Ridge - Italy [Member] | Subsequent Event [Member]
Subsequent Event [Line Items]
Equity Method Investment, Net Sales Proceeds			$ 42