Derivatives (Details) - USD ($) $ in Millions	3 Months Ended	9 Months Ended
	Sep. 30, 2015	Sep. 30, 2015	Sep. 30, 2014
After-tax Derivative Activity recorded in AOCI
Unrealized (losses) gains recognized in AOCI	$ 2	$ 2	$ (5)
Losses (gains) reclassified to income	$ 1	$ 1	$ 8