Commitments and Contingencies (Narrative) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2016	Dec. 31, 2015	Dec. 31, 2014
Loss Contingencies [Line Items]
Rent expense	$ 227	$ 212	$ 191
Outstanding fixed capital commitments related to our India development center expansion program	176
Internal Investigation and Related Matters [Member]
Loss Contingencies [Line Items]
Potential Improper Payments	$ 6