Consolidated Statements of Changes in Stockholder's Equity - USD ($) $ in Millions	Total	Common Stock	Additional Paid-in Capital	Retained Earnings	Accumulated Other Comprehensive Income (Loss)	Noncontrolling Interests
Beginning balance at Dec. 31, 2015	$ 16,593	$ 144	$ 7,868	$ 9,116	$ (750)	$ 215
Net Income Including Noncontrolling Interests	922			990		(68)
Other comprehensive income (loss), net of tax	(146)				(146)
Compensation—restricted stock units	10		13	(3)
Other	7		3	(2)		6
Net change	793		16	985	(146)	(62)
Ending balance at Dec. 31, 2016	17,386	144	7,884	10,101	(896)	153
Net Income Including Noncontrolling Interests	1,034			1,077		(43)
Other comprehensive income (loss), net of tax	52				52
Compensation—restricted stock units	(10)		(8)	(2)
Stock Issued During Period, Value, New Issues	402	3	321	78
Dividends Paid	(500)			(500)
TaxCutsandJobsActReclassification				182	(182)
Other	(9)	1	0	0		(10)
Net change	969	4	313	835	(130)	(53)
Ending balance at Dec. 31, 2017	18,355	148	8,197	10,936	(1,026)	100
Net Income Including Noncontrolling Interests	1,049			1,073		(24)
Other comprehensive income (loss), net of tax	(319)				(319)
Compensation—restricted stock units	(5)		0	(5)
sharerepurchase	(2,496)	(16)		(2,480)
Other	(4)	0	(21)	0	21	(4)
Net change	(1,775)	(16)	(21)	(1,412)	(298)	(28)
Ending balance at Dec. 31, 2018	$ 16,580	$ 132	$ 8,176	$ 9,524	$ (1,324)	$ 72