Shareholders' Equity Changes in Accumulated Other Comprehensive Income (Loss) (Details) - USD ($) $ in Millions	12 Months Ended
	Dec. 31, 2018	Dec. 31, 2017	Dec. 31, 2016
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	$ (1,519)	$ (1,610)
Other comprehensive (loss) income before reclassifications	(230)	131
Reclassifications	3	(40)
Ending balance	(1,746)	(1,519)	$ (1,610)
Other Comprehensive Income (Loss), Net of Tax	227	(91)	(31)
Accumulated Translation Adjustment [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(1,484)	(1,614)
Other comprehensive (loss) income before reclassifications	(240)	130
Reclassifications	0	0
Ending balance	(1,724)	(1,484)	(1,614)
Other Comprehensive Income (Loss), Net of Tax	(240)	130
Defined Benefit Pension [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Beginning balance	(26)	13
Other comprehensive (loss) income before reclassifications	10	1
Reclassifications	2	(40)
Ending balance	(14)	(26)	13
Other Comprehensive Income (Loss), Net of Tax	12	(39)
Deferred Loss on Derivatives [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Other comprehensive (loss) income before reclassifications	0	0
Reclassifications	1	0
Other Comprehensive Income (Loss), Net of Tax	1	0
Fair Value Hedging [Member] | Interest Rate Swap [Member]
Accumulated Other Comprehensive Income (Loss) [Line Items]
Deferred (Gain) Loss on Discontinuation of Fair Value Hedge	$ (8)	$ (9)	$ (9)