Accumulated Other Comprehensive Income (Details) - USD ($) $ in Millions	3 Months Ended
Mar. 31, 2019	Mar. 31, 2018
Cumulative Translation Adjustment Summary [Roll Forward]
Beginning balance	$ (829)	$ (419)
Net gain/(loss) on Foreign Currency Transaction	20	113
Ending balance	(809)	(306)
Other Comprehensive Income (Loss), Foreign Currency Translation Adjustment, Tax [Abstract]
Net gain/(loss) on foreign currency translation, tax adjustment	$ 0	$ 0

Accumulated adjustment, net of tax, that results from the process of translating subsidiary financial statements and foreign equity investments into the reporting currency from the functional currency of the reporting entity, net of reclassification of realized foreign currency translation gains or losses.

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Namespace Prefix:	us-gaap_
Data Type:	xbrli:monetaryItemType
Balance Type:	credit
Period Type:	instant