Consolidated Statements of Changes in Shareholder's Equity - USD ($) $ in Millions	Total	Common stock	Additional paid-in capital	Retained earnings	Accumulated other comprehensive income/(loss)	Noncontrolling interests
Balance at Dec. 31, 2017	$ 3,264	$ 745	$ 2	$ 2,969	$ (592)	$ 140
Increase (Decrease) in Shareholder's Equity [Roll Forward]
Profit of consolidated companies	95			91		4
Foreign currency translation, net of tax	71				65	6
Derivative financial instruments, net of tax	(6)				(6)
Balance at Mar. 31, 2018	3,424	745	2	3,060	(533)	150
Balance at Dec. 31, 2018	2,849	745	2	2,874	(925)	153
Increase (Decrease) in Shareholder's Equity [Roll Forward]
Profit of consolidated companies	104			98		6
Foreign currency translation, net of tax	15				13	2
Derivative financial instruments, net of tax	(14)				(14)
Adjustment to adopt new accounting guidance | Accounting Standards Update 2018-02	0			(97)	97
Balance at Mar. 31, 2019	$ 2,954	$ 745	$ 2	$ 2,875	$ (829)	$ 161