Other Financial Data - Schedule of Other Current Assets (Details) - USD ($) $ in Millions	Mar. 31, 2018	Jan. 01, 2018	Dec. 31, 2017
Other Financial Data [Abstract]
Taxes receivable	$ 118		$ 114
Prepaid expenses	142		126
Receivables from divested business	6		28
Cost to fulfill contracts with customers	240		0
Other	103		21
Total	$ 609	$ 587	$ 289