Income and Other Taxes - Unrecognized Tax Benefits Rollforward (Details) - USD ($) $ in Millions		12 Months Ended
		Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Reconciliation of Unrecognized Tax Benefits, Excluding Amounts Pertaining to Examined Tax Returns [Roll Forward]
Balance, Beginning		$ 125	$ 165	$ 222
Additions (Reductions) related to current year		2	1	(9)
Additions related to prior years positions		3	10	0
Reductions related to prior years positions		(13)	(46)	(31)
Settlements with taxing authorities	[1]	(6)	(5)	0
Reductions related to lapse of statute of limitations		(3)	(3)	(2)
Currency		0	3	(2)
Tax Positions assumed in Conduent Separation		0	0	(13)
Balance, Ending		108	125	165
Unrecognized Tax Benefits, Reasonably Possible but Uncertainty of Timing		8	8	5
Unrecognized Tax Benefits, Income Tax Penalties and Interest Accrued		$ 2	$ 5	$ 10

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