CONSOLIDATED STATEMENTS OF EQUITY - USD ($) $ in Millions	Total	Common shares [Member]	Additional paid-in capital [Member]	Retained earnings [Member]	Treasury shares [Member]	AOCI Attributable to Parent [Member]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting policies | Cumulative effect of change in accounting policies - Revenue recognition	$ (3)			$ (3)
Beginning balance, restated	6,289	$ 3	$ 7,765	10,348	$ (12,027)	$ 200
Beginning balance (in shares) at Dec. 31, 2016		154,759,904
Beginning balance at Dec. 31, 2016	6,292	$ 3	7,765	10,351	(12,027)	200
Comprehensive income (loss) [Abstract]
Net income	403			403
Other comprehensive income (loss), net of tax	19					19
Total comprehensive income	422
Dividends to shareholders	(121)			(121)
Repurchase of common shares (in shares)		(4,118,826)
Repurchase of common shares	(509)				(509)
Share-based compensation plans (in shares)		2,347,526
Share-based compensation plans	143		92		51
Ending balance (in shares) at Mar. 31, 2017		152,988,604.000000
Ending balance at Mar. 31, 2017	6,224	$ 3	7,857	10,630	(12,485)	219
Beginning balance (in shares) at Dec. 31, 2017		146,634,664
Beginning balance at Dec. 31, 2017	5,995	$ 3	8,085	11,326	(13,648)	229
Comprehensive income (loss) [Abstract]
Net income	594			594
Other comprehensive income (loss), net of tax	(233)					(233)
Total comprehensive income	361
Dividends to shareholders	(125)			(125)
Repurchase of common shares (in shares)		(3,003,729)
Repurchase of common shares	(482)				(482)
Share-based compensation plans (in shares)		1,387,422
Share-based compensation plans	91		31		60
Ending balance (in shares) at Mar. 31, 2018		145,018,357.000000
Ending balance at Mar. 31, 2018	5,840	$ 3	$ 8,116	11,796	$ (14,070)	(5)
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Cumulative effect of change in accounting policies | Cumulative effect of change in accounting policies - Recognition and measurement of financial instruments	$ 0			$ 1		$ (1)