Expenses - Costs Related To Acquisition And Restructuring (Details) - USD ($) $ in Millions	3 Months Ended		9 Months Ended
	Sep. 30, 2015	Sep. 30, 2014	Sep. 30, 2015	Sep. 30, 2014
Other Expenses [Abstract]
Acquisition costs	$ 7	$ 12	$ 15	$ 48
Restructuring charges, net	3	8	4	33
Total acquisition and restructuring costs	$ 10	$ 20	$ 19	$ 81