Income and Other Taxes - Unrecognized Tax Benefits Rollforward (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2015	Dec. 31, 2014	Dec. 31, 2013
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance, Beginning		$ 240	$ 267	$ 201
Additions related to current year		39	16	60
Additions related to prior years positions		0	10	39
Reductions related to prior years positions		(16)	(35)	(19)
Settlements with taxing authorities	[1]	(5)	(10)	0
Reductions related to lapse of statute of limitations		(9)	(6)	(14)
Currency		(2)	(2)	0
Balance, Ending		247	240	267
Unrecognized Tax Benefits, Reasonably Possible but Uncertainty of Timing		31	39	36
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued		$ 15	$ 17	$ 20

[1] Majority of settlements did not result in the utilization of cash.