Other Financial Data - Schedule of Other Income (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2017	Dec. 31, 2016	Dec. 31, 2015
Other Financial Data [Abstract]
Foreign currency remeasurement gain (loss)	$ (37)	$ (2)	$ 30
Net gain (loss) on disposal of businesses	(16)	39	82
Equity earnings	12	13	13
Income (loss) on financial instruments	2	(14)	(24)
Other	0	0	(1)
Other income	$ (39)	$ 36	$ 100